Semiconductor light-emitting device and light-emitting display therewith

ABSTRACT

A semiconductor light-emitting device has a semiconductor light-emitting element for emitting light with emission wavelengths of 390 to 420 nm, wherein the wavelengths of light from the semiconductor light-emitting element are converted by a fluorescent substance having a monochromatic emission peak. The emission wavelengths of 390 to 420 nm, which have almost no adverse effect on human bodies and components of the semiconductor light-emitting device, are in a low human visibility range. Since light whose wavelengths are converted by the fluorescent substance are hardly affected by direct light from the semiconductor light-emitting element, light from the fluorescent substance has a favorable color tone. Also, the semiconductor light-emitting device allows desired luminous colors to be obtained only by changing fluorescent substance materials without changing the structure of the semiconductor light-emitting device or the semiconductor light-emitting element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 09/957,472 filed Sep. 21,2001, now U.S. Pat. No. 7,271,423 issued Sep. 18, 2007.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor light-emitting deviceutilized in an LED (Light Emitting Diode) in use for a light source fora backlight of a liquid crystal display, cellular phone, mobile dataterminal or the like, a display device utilized in indoor or outdooradvertisements or the like, an indicator of various portable equipment,a backlighted switch, a light source for OA (Office Automation)equipment or the like. The present invention relates, in particular, toa semiconductor light-emitting device in which the wavelength ofoutgoing light from a semiconductor light-emitting element is convertedby using a fluorescent substance and which can be utilized as a lightsource of various luminous colors and a light-emitting display deviceusing the same.

A semiconductor light-emitting device, characterized by its small sizeand low power consumption, can emit high-brightness light in a stablemanner and thereby is widely used as a light source in various displaydevices. Furthermore, the semiconductor light-emitting device is alsoutilized as a light source for reading data records in various dataprocessors. A semiconductor light-emitting element in use for asemiconductor light-emitting device that emits long-wavelength visiblelight, which has been widely used in practice, can emit high-brightnesslight from red to green depending on the semiconductor material,formation conditions or the like of a light-emitting layer to be used.Meanwhile, a semiconductor light-emitting element that emitsshort-wavelength visible light from blue to purple has been developed inrecent years and started being used in general practice.

A LED display utilizing a semiconductor light-emitting device havingluminous colors of, for example, three primary colors, R (Red), G(Green) and B (Blue), by using semiconductor light-emitting elements ofthese various luminous colors has started to be commercially available.

Furthermore, Patent Publication No. 2927279, for example, discloses asemiconductor light-emitting device wherein a semiconductorlight-emitting element emitting short-wavelength visible light from blueto purple and a fluorescent substance are combined to obtain white bymixing colors of outgoing light from the semiconductor light-emittingelement and light whose wavelength is converted by the fluorescentsubstance.

Japanese Patent Laid-Open Publication No. 10-163535 discloses asemiconductor light-emitting device wherein a semiconductorlight-emitting element having blue or blue purple luminous color and oneor more kinds of fluorescent substances that absorb light from thissemiconductor light-emitting element to emit light in the visible rangeare combined to obtain high-brightness compact white luminous colors.The luminous colors of the semiconductor light-emitting element and theluminous colors of the fluorescent substances are in mutuallycomplementary color relations. The fluorescent substance is selected sothat the luminous color of the semiconductor light-emitting element andthe luminous color of the fluorescent substance are added to emit whitelight.

Furthermore, Japanese Patent Laid-Open Publication No. 10-12925discloses a semiconductor light-emitting device having a semiconductorlight-emitting element that emits ultraviolet light and near-ultravioletlight and a fluorescent substance that emits fluorescent light by lightfrom this semiconductor light-emitting element. This semiconductorlight-emitting element is usually a semiconductor light-emitting elementthat emits blue light, but emits ultraviolet light and near-ultravioletlight by allowing a pulsed high current to flow. It is disclosed that aplurality of luminous colors can be obtained by using a single kind ofsemiconductor light-emitting element only by changing the kind offluorescent substance.

Furthermore, Japanese Patent Laid-Open Publication No. 9-153644discloses a dot-matrix type display device having a light-emitting layerthat is formed by using a group-III nitride substance semiconductor andemits ultraviolet rays having a peak wavelength of 380 nm and threekinds of fluorescent substance layers, which receive the ultravioletrays from this light-emitting layer and emit light in three primarycolors, red, blue and green, respectively.

However, these conventional techniques have problems as described below.

A semiconductor light-emitting element having luminous colors from redto green for use in a long-wavelength visible light semiconductorlight-emitting device and a semiconductor light-emitting element thatemits short-wavelength visible light from blue to purple vary inmaterials to be used and element shapes depending on the wavelengths oftheir emitted light. Therefore, when semiconductor elements havingdifferent wavelengths are mounted to obtain a semiconductorlight-emitting device, a plurality of different mounting materials anddifferent mounting processes are required and the manufacturing processbecomes complicated with increased costs.

Furthermore, currents to the plurality of semiconductor light-emittingelements need to be adjusted to obtain white light in a favorable colorby using a plurality of semiconductor light-emitting elements havingdifferent luminous colors. Therefore, a problem arises that thesemiconductor light-emitting device becomes complicated. Furthermore,when a light-emitting display device is formed by using a plurality ofthe semiconductor light-emitting devices, a large amount of color tonesof the semiconductor light-emitting elements need to be adjusted andthus the manufacturing process becomes complicated.

Furthermore, in the semiconductor light-emitting devices disclosed inthe above Patent Publication No. 2927279 and Japanese Patent Laid-OpenPublication No. 10-163535, the colors of the outgoing light from thesemiconductor light-emitting element and the light emitted from thefluorescent substance, which is in complementary color relations withthis outgoing light, are mixed to obtain white luminous color. Thisresults in poor light use efficiency is and an unfavorable color tone.For example, when a semiconductor light-emitting device wherein whitelight is obtained by mixing blue outgoing light of the semiconductorlight-emitting element and yellow outgoing light of the fluorescentsubstance is used as a backlight of a liquid crystal display device,this white light contains a small light quantity of pure green and purered. Therefore, there is a small quantity of light that transmits a redcolor filter included in the liquid crystal display device. When theliquid crystal display device performs a full color display, animpression of decoloration is generated.

Furthermore, since a pulsed high current is applied to the semiconductorlight-emitting element in the semiconductor light-emitting devicedisclosed in Japanese Patent Laid-Open Publication No. 10-12925, thesemiconductor light-emitting element is destroyed or heated anddeteriorated, resulting in a short life and low reliability.Furthermore, since this semiconductor light-emitting element has itsemission wavelength peak in the ultraviolet or near ultravioletwavelength range as well as in the blue wavelength range, this bluelight is mixed with the light emitted from the fluorescent substance,resulting in a poor color tone. Furthermore, when the semiconductorlight-emitting device is deteriorated, a plurality of semiconductorlight-emitting elements having different luminous colors are notuniformly deteriorated in brightness, but a blue-wavelength component isparticularly rapidly deteriorated, resulting in changed color tones ofthe semiconductor light-emitting device. Furthermore, since thesemiconductor light-emitting element emits light having wavelengths fromthe vicinity of near ultraviolet (390 nm) to the ultraviolet range onthe short wavelength side, a measure for preventing influences on humanbodies needs to be taken. Furthermore, since a resin for fixing andmolding the semiconductor light-emitting element is also adverselyaffected by the light having wavelengths in the ultraviolet range, lowerreliability due to deterioration of the fixing resin or lower brightnessof emitted light due to blackening of the molding resin may occur.

Since the semiconductor light-emitting device disclosed in JapanesePatent Laid-Open Publication No. 9-153644 also utilizes light having anemission wavelength of 380 nm in the ultraviolet range, a measure forpreventing leakage of light in the ultraviolet range needs to be takento prevent influences to human bodies. Furthermore, a resin for fixingand molding a semiconductor light-emitting element is adverselyaffected, thereby resulting in deterioration of reliability and lowerbrightness of emitted light. Since the fluorescent substance layers foremitting three primary colors of red, blue and green are formed on asubstrate as well as a semiconductor layer in this semiconductorlight-emitting device, the process for manufacturing the semiconductorlight-emitting device is complicated, thereby deteriorating the yieldand reliability.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a semiconductorlight-emitting device that can emit light having a plurality of emissionwavelengths, can be easily manufactured at a low cost, achievesfavorable color tones without affecting human bodies and suffers almostno deterioration, and a light-emitting display device using the same.

To achieve the above object, the present invention provides asemiconductor light-emitting device constituted by mounting asemiconductor light-emitting element on a base substance, wherein

the semiconductor light-emitting element has outgoing light having anemission wavelength of 390 to 420 nm; and

there is included a fluorescent substance that is excited by outgoinglight from the semiconductor light-emitting element and emits red lighthaving an emission wavelength with its main emission peak in awavelength range of 600 to 670 nm.

According to the present invention, in this semiconductor light-emittingdevice, the semiconductor light-emitting element has outgoing light in ashort-wavelength range, wherein the human visibility is very low. Inaddition to this, the fluorescent substance has its main emission peakin a red emission wavelength range and thereby emits monochromatic redlight. Therefore, even if the light emitted from the fluorescentsubstance and the outgoing light directly from the semiconductorlight-emitting element are mixed, apparent color tones of the outgoinglight of the fluorescent substance are hardly changed in considerationto human visibility. That is, light from the fluorescent substance isemitted from the semiconductor light-emitting device without beingaffected by the direct light from the semiconductor light-emittingelement. Therefore, a semiconductor light-emitting device that emitsmonochromatic red light with a favorable color tone can be obtained.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in the semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur. On theother hand, when the emission wavelength of the semiconductorlight-emitting element is longer than 420 nm, outgoing light from thissemiconductor light-emitting element has an emission wavelength in avisible range. Therefore, the color of this light is mixed with that ofthe outgoing light from the fluorescent substance and thus the colortone of the luminous color of the semiconductor light-emitting device ischanged. Therefore, when the emission wavelength of the semiconductorlight-emitting element is made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achievesfavorable color tones while having almost no adverse effect on humanbodies can be obtained.

In one embodiment of the present invention, the fluorescent substance iscomposed of any one or more selected from a fluorescent substance groupconsisting of:

-   -   M₂O₂S:Eu (M is any one or more elements selected from La, Gd and        Y);    -   0.5MgF₂.3.5MgO.GeO₂:Mn;    -   Y₂O₃:Eu;    -   Y(P, V)O₄:Eu; and    -   YVO₄:Eu.

According to the above embodiment, when a semiconductor light-emittingelement having outgoing light having any wavelength in a range of 390 to420 nm is used, the fluorescent substance can be selected depending onthe wavelengths of the outgoing light of the semiconductorlight-emitting element. Therefore, a semiconductor light-emitting devicethat emits monochromatic red light having emission wavelengths with itsfavorable emission peak in the red wavelength range can be obtained.Since substantially all the wavelengths in the wavelength range of theoutgoing light of the semiconductor light-emitting element can beconverted to red wavelengths by combining a plurality of fluorescentsubstances, a semiconductor light-emitting device that emitsmonochromatic red light in high efficiency can be obtained.

The present invention also provides a semiconductor light-emittingdevice constituted by mounting a semiconductor light-emitting element ona base substance, wherein

the semiconductor light-emitting element has outgoing light having anemission wavelength in a range of 390 to 420 nm; and

there is included a fluorescent substance that is excited by outgoinglight from the semiconductor light-emitting element and emits greenlight having an emission wavelength with its main emission peak in awavelength range of 500 to 540 nm.

According to the present invention, in the semiconductor light-emittingdevice, the semiconductor light-emitting element has outgoing light in ashort wavelength range, wherein the human visibility is very low. Inaddition to this, the fluorescent substance has its main emission peakin a green emission wavelength range and thereby emits monochromaticgreen light. Therefore, even if the light emitted from the fluorescentsubstance and the outgoing light directly from the semiconductorlight-emitting element are mixed, apparent color tones of the outgoinglight of the fluorescent substance are hardly changed in considerationof human visibility. That is, light from the fluorescent substance isemitted from the semiconductor light-emitting device without beingaffected by the direct light from the semiconductor light-emittingelement. Therefore, a semiconductor light-emitting device that emitsmonochromatic green light with a favorable color tone can be obtained.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in the semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur. On theother hand, when the emission wavelength of the semiconductorlight-emitting element is longer than 420 nm, outgoing light from thissemiconductor light-emitting element has an emission wavelength in avisible range. Therefore, the color of this light is mixed with that ofthe outgoing light from the fluorescent substance and the color tone ofthe luminous color of the semiconductor light-emitting device ischanged. Therefore, when the emission wavelength of the semiconductorlight-emitting element is made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achieves afavorable color tone while having almost no adverse effect on humanbodies can be obtained.

In one embodiment of the present invention, the fluorescent substance iscomposed of any one or more selected from a fluorescent substance groupconsisting of:

-   -   RMg₂Al₁ ₆O₂ ₇:Eu, Mn (R is any one or both elements selected        from Sr and Ba);    -   RMgAl₁ ₀O₁ ₇:Eu, Mn (R is any one or both elements selected from        Sr and Ba);    -   ZnS:Cu;    -   SrAl₂O₄:Eu;    -   SrAl₂O₄:Eu, Dy;    -   ZnO:Zn;    -   Zn₂Ge₂O₄:Mn;    -   Zn₂ SiO₄:Mn; and    -   Q₃MgSi₂O₈:Eu, Mn (Q is any one or more elements selected from        Sr, Ba and Ca).

According to the above embodiment, since the optimal fluorescentsubstance can be selected depending on the emission wavelengths of thesemiconductor light-emitting element, a semiconductor light-emittingdevice that emits monochromatic green light having emission wavelengthswith its favorable emission peak in the green wavelength range can beobtained. Since substantially all the wavelengths in the wavelengthrange of the outgoing light of the semiconductor light-emitting elementcan be converted to green wavelengths by combining a plurality offluorescent substances, a semiconductor light-emitting device that emitsmonochromatic green light in high efficiency can be obtained.

The present invention provides a semiconductor light-emitting deviceconstituted by mounting a semiconductor light-emitting element on a basesubstance, wherein

the semiconductor light-emitting element has outgoing light having anemission wavelength in a range of 390 to 420 nm; and

there is included a fluorescent substance that is excited by outgoinglight from the semiconductor light-emitting element and emits blue lighthaving an emission wavelength with its main emission peak in awavelength range of 410 to 480 nm.

According to the present invention, in the semiconductor light-emittingdevice, the semiconductor light-emitting element has outgoing light in ashort wavelength range, wherein the human visibility is very low. Inaddition to this, the fluorescent substance has its main emission peakin a blue emission wavelength range and thereby emits monochromatic bluelight. Therefore, even if the light emitted from the fluorescentsubstance and the outgoing light directly from the semiconductorlight-emitting element are mixed, apparent color tones of the outgoinglight of the fluorescent substance are hardly changed in considerationto human visibility. That is, light from the fluorescent substance isemitted from the semiconductor light-emitting device without beingaffected by the direct light from the semiconductor light-emittingelement. Therefore, a semiconductor light-emitting device that emitsmonochromatic blue light with a favorable color tone can be obtained.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in the semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur. On theother hand, when the emission wavelength of the semiconductorlight-emitting element is longer than 420 nm, outgoing light from thissemiconductor light-emitting element has emission wavelengths in avisible range. Therefore, the color of this light is mixed with that ofthe outgoing light from the fluorescent substance and the color tone ofthe luminous color of the semiconductor light-emitting device ischanged. Therefore, when the emission wavelength of the semiconductorlight-emitting element is made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achieves afavorable color tone while having almost no adverse effect on humanbodies can be obtained.

In one embodiment of the present invention, the fluorescent substance iscomposed of any one or more selected from a fluorescent substance groupconsisting of:

-   -   A₁ ₀(PO₄)₆Cl₂:Eu (A is any one or more elements selected from        Sr, Ca, Ba, Mg and Ce);    -   XMg₂Al₁ ₆O₂ ₇:Eu (X is any one or both elements selected from Sr        and Ba);    -   XMgAl₁ ₀O₁ ₇:Eu (X is any one or both elements selected from Sr        and Ba);    -   ZnS:Ag;    -   Sr₁ ₀(PO₄)₆Cl₂:Eu;    -   Ca₁ ₀(PO₄)₆F₂:Sb;    -   Z₃ MgSi₂O₈:Eu (Z is any one or more elements selected from Sr,        Ca and Ba);    -   SrMgSi₂O₈:Eu;    -   Sr₂P₂O₇:Eu; and    -   CaAl₂O₄:Eu, Nd.

According to the above embodiment, since the optimal fluorescentsubstance can be selected depending on the emission wavelengths of thesemiconductor light-emitting element, a semiconductor light-emittingdevice that emits monochromatic blue light having emission wavelengthswith its favorable emission peak in the blue wavelength range can beobtained. Since substantially all the wavelengths in the wavelengthrange of the outgoing light of the semiconductor light-emitting elementcan be converted to blue wavelengths by combining a plurality offluorescent substances, a semiconductor light-emitting device thatachieves monochromatic blue light in high efficiency can be obtained.

The present invention provides a semiconductor light-emitting deviceconstituted y mounting a semiconductor light-emitting element on a basesubstance, wherein

the semiconductor light-emitting element has outgoing light having anemission wavelength in a range of 390 to 420 nm; and

there is included a fluorescent substance that is excited by outgoinglight from the semiconductor light-emitting element and emits blue greenlight having an emission wavelength with its main emission peak in awavelength range of 480 to 500 nm.

According to the present invention, in the semiconductor light-emittingdevice, the semiconductor light-emitting element has outgoing light in ashort wavelength range, wherein the human visibility is very low. Inaddition to this, the fluorescent substance has its main emission peakin a blue green emission wavelength range and thereby emitsmonochromatic blue green light. Therefore, even if the light emittedfrom the fluorescent substance and the outgoing light directly from thesemiconductor light-emitting element are mixed, apparent color tones ofthe outgoing light of the fluorescent substance are hardly changed inconsideration to human visibility. That is, light from the fluorescentsubstance is emitted from the semiconductor light-emitting devicewithout being affected by the direct light from the semiconductorlight-emitting element. Therefore, a semiconductor light-emitting devicethat emits monochromatic blue green light with a favorable color tonecan be obtained.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in the semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur. On theother hand, when the emission wavelength of the semiconductorlight-emitting element is longer than 420 nm, outgoing light from thissemiconductor light-emitting element has an emission wavelength in avisible range. Therefore, the color of this light is mixed with that ofthe outgoing light from the fluorescent substance and the color tone ofthe luminous color of the semiconductor light-emitting device ischanged. Therefore, when the emission wavelength of the semiconductorlight-emitting element is made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achieves afavorable color tone while having almost no adverse effect on humanbodies can be obtained.

In one embodiment of the present invention, the fluorescent substance iscomposed of any one or more selected from a fluorescent substance groupconsisting of:

-   -   Sr₄Al₁ ₄O₂ ₅:Eu;    -   Sr₄Al₁ ₄O₂ ₅:Eu, Dy;    -   L₁ ₀(PO₄)₆Cl₂:Eu (L is any one or more elements selected from        Ba, Ca and Mg); and    -   Sr₂Si₃O₈.2SrCl₂:Eu.

According to the above embodiment, since the optimal fluorescentsubstance can be selected depending on the emission wavelength of thesemiconductor light-emitting element, a semiconductor light-emittingdevice that emits monochromatic blue green light having emissionwavelengths with its favorable emission peak in the blue greenwavelength range can be obtained. Since substantially all thewavelengths in the wavelength range of the outgoing light of thesemiconductor light-emitting element can be converted to blue greenwavelengths by combining a plurality of fluorescent substances, asemiconductor light-emitting device that achieves monochromatic bluegreen light in high efficiency can be obtained.

The present invention provides a semiconductor light-emitting deviceconstituted by mounting a semiconductor light-emitting element on a basesubstance, wherein

the semiconductor light-emitting element has outgoing light having anemission wavelength in a range of 390 to 420 nm; and

there is included a fluorescent substance that is excited by outgoinglight from the semiconductor light-emitting element and emits orangelight having an emission wavelength with its main emission peak in awavelength range of 570 to 600 nm.

According to the present invention, in the semiconductor light-emittingdevice, the semiconductor light-emitting element has outgoing light in ashort wavelength range, wherein the human visibility is very low. Inaddition to this, the fluorescent substance has its main emission peakin an orange emission wavelength range and thereby emits monochromaticorange light. Therefore, even if the light emitted from the fluorescentsubstance and the outgoing light directly from the semiconductorlight-emitting element are mixed, apparent color tones of the outgoinglight of the fluorescent substance are hardly changed in considerationto human visibility. That is, light from the fluorescent substance isemitted from the semiconductor light-emitting device without beingaffected by the direct light from the semiconductor light-emittingelement. Therefore, a semiconductor light-emitting device that emitsmonochromatic orange light with a favorable color tone can be obtained.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in the semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur. On theother hand, when the emission wavelength of the semiconductorlight-emitting element is longer than 420 nm, outgoing light from thissemiconductor light-emitting element has emission wavelengths in avisible range. Therefore, the color of this light is mixed with that ofthe outgoing light from the fluorescent substance and the color tone ofthe luminous color of the semiconductor light-emitting device ischanged. Therefore, when the emission wavelength of the semiconductorlight-emitting element is made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achieves afavorable color tone while having almost no adverse effect on humanbodies can be obtained.

In one embodiment of the present invention, the fluorescent substance iscomposed of any one or more selected from a fluorescent substance groupconsisting of:

-   -   ZnS:Mn; and    -   ZnS:Cu, Mn, Co.

According to the above embodiment, since the optimal fluorescentsubstance can be selected depending on the wavelength range of thesemiconductor light-emitting element, a semiconductor light-emittingdevice that emits monochromatic orange light having emission wavelengthswith its favorable emission peak in the orange wavelength range can beobtained.

In one embodiment of the present invention, a sealing resin for sealingat least a part of the base substance and the semiconductorlight-emitting element is included; and

-   -   the sealing resin contains the fluorescent substance.

According to the above embodiment, since a sealing resin for sealing thesemiconductor light-emitting element contains a fluorescent substance,the wavelength of outgoing light from the semiconductor light-emittingelement is inevitably converted. Therefore, use efficiency of light fromthe semiconductor light-emitting element is favorable. Furthermore,since the fluorescent substance can be disposed while the sealing resinis formed, a process for disposing a fluorescent substance separately isnot required. Therefore, the semiconductor light-emitting device can beeasily manufactured.

Furthermore, according to this semiconductor light-emitting device, asemiconductor device that emits light having desired emissionwavelengths can be obtained without changing structures of thesemiconductor light-emitting element and the semiconductorlight-emitting device by combining a semiconductor light-emittingelement having emission wavelengths in a certain wavelength range and apredetermined fluorescent substance. That is, since a semiconductorlight-emitting device having desired emission wavelengths can beobtained only by changing the fluorescent substance in the samemanufacturing process, the manufacturing cost for the semiconductorlight-emitting device can be largely reduced.

In one embodiment of the present invention, the base substance is a leadframe having a cup-shaped mount section;

the semiconductor light-emitting element is disposed at the bottom ofthe cup-shaped mount section of the lead frame and electricallyconnected to another lead frame by wire bonding; and

at least a part of the two lead frames and the semiconductorlight-emitting element are sealed with the sealing resin.

According to the above embodiment, since the wavelength of outgoinglight from the semiconductor light-emitting element collected by thecup-shaped mount section is reliably converted by a sealing resincontaining the fluorescent substance, a semiconductor light-emittingdevice with favorable directivity, light-emitting efficiency and colortones can be obtained.

In one embodiment of the present invention, the base substance is aninsulator connected to ends of a pair of lead frames;

the semiconductor light-emitting element is connected to metallic wiringformed on the insulator; and

at least a part of the pair of lead frames, the insulator and thesemiconductor light-emitting element are sealed with the sealing resin.

According to the above embodiment, since the semiconductorlight-emitting element is directly connected to the metallic wiring onthe substrate with, for example, a metal bump or the like, work forconnecting the semiconductor light-emitting element and the lead frameswith a metallic wire or the like can be omitted. Further, the wavelengthof outgoing light from the semiconductor light-emitting element isreliably converted by a fluorescent substance contained in the sealingresin. Therefore, a semiconductor light-emitting device with favorablemanufacturing efficiency, light-emitting efficiency and color tones canbe obtained.

In one embodiment of the present invention, the base substance is a leadframe having a cup-shaped mount section;

the semiconductor light-emitting element is disposed at the bottom ofthe cup-shaped mount section of the lead frame and electricallyconnected to another lead frame by wire bonding;

the fluorescent substance is filled in the cup-shaped mount section; and

at least a part of the two lead frames, the semiconductor light-emittingelement and the fluorescent substance are sealed with a sealing resin.

According to the above embodiment, since a fluorescent substance isfilled in the cup-shaped mount section, into which light from thesemiconductor light-emitting element is collected, the wavelength of thelight from the semiconductor light-emitting element is reliablyconverted, thereby improving light use efficiency. Furthermore, since anarea in which the fluorescent substance is disposed is smaller than in asemiconductor light-emitting device that does not collect light from thesemiconductor light-emitting element, the amount of the fluorescentsubstance to be used can be reduced.

In one embodiment of the present invention, the base substance is a leadframe having a cup-shaped mount section;

the semiconductor light-emitting element is disposed at the bottom ofthe cup-shaped mount section of the lead frame and electricallyconnected to another lead frame by wire bonding;

a coating member is filled in the cup-shaped mount section and thefluorescent substance is disposed on the coating member; and

at least a part of the two lead frames, the semiconductor light-emittingelement, the coating member and the fluorescent substance are sealedwith a sealing resin.

According to the above embodiment, since the fluorescent substance isdisposed on the coating member filled in the mount section, the amountof the fluorescent substance to be used can be reduced as compared witha case where the fluorescent substance is filled in the whole mountsection. Furthermore, distances between a light-emitting section of thesemiconductor light-emitting element and the fluorescent substance aremade substantially uniform by the coating member, a semiconductorlight-emitting device that emits uniform light without uneven coloringcan be obtained. Furthermore, since the semiconductor light-emittingelement and the fluorescent substance are made distant by the coatingmember, there is almost no electrical or thermal deterioration of thefluorescent substance due to the semiconductor light-emitting element.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected themetallic wiring on the substrate;

a sealing resin for sealing the semiconductor light-emitting element isincluded; and

the sealing resin contains the fluorescent substance.

According to the above embodiment, in this semiconductor light-emittingdevice, semiconductor light-emitting elements of the same shape or onekind are connected onto the metallic wiring with, for example, ametallic wire of Au, Al, Cu or the like or directly connected with metalbumps or the like without using metallic wires or the like. Therefore,as compared with a conventional case, wherein semiconductorlight-emitting devices of different shapes are manufactured by usingsemiconductor light-emitting elements of different shapes correspondingto respective luminous colors, the process of manufacturing thesemiconductor light-emitting device is simple. In this semiconductorlight-emitting device, since a semiconductor light-emitting devicehaving desired emission wavelengths can be obtained only by disposing apredetermined fluorescent substance corresponding to a desiredwavelength, a semiconductor light-emitting device can be more easilymanufactured at a lower cost than a conventional device.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate and disposed in a recessed portion;and

the fluorescent substance is filled in the recessed portion.

According to the above embodiment, since the fluorescent substance isfilled in the recessed portion in the substrate, the amount of thefluorescent substance to be used can be reduced and a semiconductorlight-emitting device that has favorable light-emitting efficiency andemits monochromatic light with favorable color tones can be obtained ata low manufacturing cost.

In one embodiment of the present invention, the recessed portion isformed by a frame disposed on the substrate.

According to the above embodiment, since a frame is disposed on thesubstrate to form the recessed portion, processing work for, forexample, cutting the substrate to form the recessed portion can beomitted. Furthermore, when the shape of a side surface of the frame onthe semiconductor light-emitting element side is processed into, forexample, a shape in which outgoing light from the semiconductorlight-emitting element is collected, efficiency of converting thewavelength of the outgoing light is further improved as well asdirectivity of the semiconductor light-emitting device. As a result, asemiconductor light-emitting device that has favorable light-emittingefficiency and emits monochromatic light with favorable color tones canbe obtained.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate and disposed in a recessed portion;

a sealing resin is filled in the recessed portion; and

the fluorescent substance is disposed on the sealing resin.

According to the above embodiment, since the fluorescent substance isdisposed on the sealing resin, a semiconductor light-emitting devicehaving desired emission wavelengths can be obtained with a furtherreduced amount of the fluorescent substance to be used as compared witha case where the fluorescent substance is filled inside the recessedportion in the substrate. Furthermore, distances between alight-emitting section of the semiconductor light-emitting element andthe fluorescent substance is made substantially uniform by the sealingresin, a semiconductor light-emitting device that emits uniform lightwithout uneven coloring can be obtained. Furthermore, since thesemiconductor light-emitting element and the fluorescent substance aremade distant by the sealing resin, electrical and thermal effects of thesemiconductor light-emitting element on the fluorescent substance can bereduced, thereby stabilizing performance of the semiconductorlight-emitting device.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate;

a reflector for reflecting at least a part of outgoing light from thesemiconductor light-emitting element is included;

a sealing resin for sealing the semiconductor light-emitting element andtransmitting reflected light from the reflector is included; and

the fluorescent substance is contained in the sealing resin.

According to the above embodiment, in this semiconductor light-emittingdevice, semiconductor light-emitting elements of the same shape or onekind are connected onto the metallic wiring on the substrate with, forexample, metallic wires of Au, Al, Cu or the like or directly connectedwith metal bumps or the like without using metallic wires or the like.Therefore, as compared with a conventional case, wherein semiconductorlight-emitting devices of different shapes are manufactured by usingsemiconductor light-emitting elements of different shapes correspondingto respective luminous colors, the process of manufacturing thesemiconductor light-emitting device is simple. In this semiconductorlight-emitting device, since a semiconductor light-emitting devicehaving desired emission wavelengths can be obtained only by disposing apredetermined fluorescent substance corresponding to a desiredwavelength, a semiconductor light-emitting device can be more easilymanufactured at a lower cost than a conventional device.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate;

a reflector for reflecting at least a part of outgoing light from thesemiconductor light-emitting element is included;

a shielding body for shielding light directly emitted from thesemiconductor light-emitting element to the outside of the semiconductorlight-emitting device is included;

a sealing resin for sealing the semiconductor light-emitting element andtransmitting reflected light from the reflector is included; and

a layer of the fluorescent substance is formed on a surface of thereflector that reflects light.

According to the above embodiment, since a layer of the fluorescentsubstance is formed on a surface of the reflector that reflects light,the wavelength of light reflected by the reflector is reliablyconverted. Furthermore, outgoing light from the semiconductorlight-emitting element is reflected on the reflecting surface andemitted to the outside of the semiconductor light-emitting device whileleakage outside the semiconductor light-emitting device is prevented bythe shielding body, the wavelengths of almost all the light areconverted. Therefore, this semiconductor light-emitting device canefficiently obtain desired luminous colors by using a small amount ofthe fluorescent substance formed only on the reflecting surface.Furthermore, since the fluorescent substance layer is formed on areflecting surface of the reflector with a predetermined distance fromthe semiconductor light-emitting element, distances between thelight-emitting section of the semiconductor light-emitting element andthe fluorescent substance become substantially uniform and asemiconductor light-emitting device that emits uniform light withoutuneven coloring can be obtained. Furthermore, since the semiconductorlight-emitting element and the fluorescent substance are made distant,electrical and thermal effects of the semiconductor light-emittingelement on the fluorescent substance are relieved, thereby stabilizingperformance of the semiconductor light-emitting device.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate;

at least a light-emitting section of the semiconductor light-emittingelement is disposed in a recessed portion in the substrate;

a reflector for reflecting at least a part of outgoing light from thesemiconductor light-emitting element is included;

a sealing resin for sealing the semiconductor light-emitting element andtransmitting reflected light from the reflector is included; and

a layer of the fluorescent substance is formed on a surface of thereflector that reflects light.

According to the above embodiment, since the semiconductorlight-emitting element is disposed in the recessed portion, light fromthe semiconductor light-emitting element is not emitted directly to theoutside of the semiconductor light-emitting device, but inevitablyreflected by the reflector so that its wavelength is converted and thenemitted to the outside of the semiconductor light-emitting device.Therefore, this semiconductor light-emitting device can emit outgoinglight with favorable color tones.

In one embodiment of the present invention, the base substance is asubstrate provided with metallic wiring;

the semiconductor light-emitting element is electrically connected tothe metallic wiring on the substrate;

a reflector for reflecting at least a part of outgoing light from thesemiconductor light-emitting element is included;

a sealing resin for sealing the semiconductor light-emitting element andtransmitting reflected light from the reflector is included; and

a layer of the fluorescent substance is formed on a surface of thesealing resin that reflects light.

According to the above embodiment, by a layer of the fluorescentsubstance formed on a surface of the sealing resin that reflects light,the wavelength of outgoing light from the semiconductor light-emittingelement is converted immediately before emitted from the semiconductorlight-emitting device. That is, since the wavelengths of all the lightfrom semiconductor light-emitting device are converted, a semiconductorlight-emitting device with favorable light use efficiency can beobtained. Furthermore, since the fluorescent substance layer ispositioned with a predetermined distance from the semiconductorlight-emitting element, distances between the light-emitting section ofthe semiconductor light-emitting element and the fluorescent substancebecome substantially uniform and thus a semiconductor light-emittingdevice that emits uniform light without uneven coloring can be obtained.Furthermore, since the semiconductor light-emitting element and thefluorescent substance are made distant, electrical and thermal effectsof the semiconductor light-emitting element on the fluorescent substanceare relieved, thereby stabilizing performance of the semiconductorlight-emitting device.

In one embodiment of the present invention, the semiconductorlight-emitting element has outgoing light having emission wavelengths of390 to 420 nm;

a first fluorescent substance, a second fluorescent substance and athird fluorescent substance are included;

the first fluorescent substance has red outgoing light having emissionwavelengths with its main emission peak in a wavelength range of 600 to670 nm;

the second fluorescent substance has green outgoing light havingemission wavelengths with its main emission peak in a wavelength rangeof 500 to 540 nm;

the third fluorescent substance has blue outgoing light having emissionwavelengths with its main emission peak in a wavelength range of 410 to480 nm; and

the sum of colors of light emitted from the first, second and thirdfluorescent substances is a white color.

According to the above constitution, the semiconductor light-emittingelement has a short wavelength range, wherein human visibility is verylow. In addition to this, light emitted from the first to thirdfluorescent substances is monochromatic light having their main peakemission wavelengths in the red, green and blue wavelength ranges,respectively. Therefore, even if outgoing light from the first to thirdfluorescent substances and outgoing light direct from the semiconductorlight-emitting element are mixed, apparent color tones of the outgoinglight of the semiconductor light-emitting device are hardly changed inconsideration to human visibility. That is, no light from the first tothird fluorescent substances is affected by direct light from thesemiconductor light-emitting element. Therefore, a semiconductorlight-emitting device having a white luminous color with a favorablecolor tone can be obtained. Furthermore, among outgoing light from thesemiconductor light-emitting device, light directly from thesemiconductor light-emitting element to the outside of the semiconductorlight-emitting device is not mixed with light from the fluorescentsubstances in color in the human visible range. Therefore, even thoughlight-emitting performance of the semiconductor light-emitting elementis deteriorated with a secular change after use of the semiconductorlight-emitting device for a long period, only the brightness of thesemiconductor light-emitting device is deteriorated, but the color tonesare not changed. Therefore, the semiconductor light-emitting device canstably obtain light having white light with a favorable color tone.

Furthermore, since the semiconductor light-emitting element has outgoinglight having emission wavelengths of 390 to 420 nm in this semiconductorlight-emitting device, components of the semiconductor light-emittingdevice such as, for example, a sealing resin and so forth are hardlydamaged and there is almost no action harmful to human bodies. If theemission wavelength of the semiconductor light-emitting element isshorter than 390 nm, for example, the sealing resin is damaged andtrouble such as opacification, blackening or the like may occur.Therefore, when the emission wavelengths of the semiconductorlight-emitting element are made in a range of 390 to 420 nm,deterioration of components of the semiconductor light-emitting devicecan be reduced and a semiconductor light-emitting device that achieves afavorable color tone while having almost no adverse effect to human bodycan be obtained.

In one embodiment of the present invention, the first fluorescentsubstance is composed of any one or more selected from a fluorescentsubstance group consisting of:

-   -   M₂O₂S:Eu (M is any one or more elements selected from La, Gd and        Y);    -   0.5MgF₂.3.5MgO.GeO₂:Mn;    -   Y₂O₃:Eu,    -   Y(P, V)O₄:Eu; and    -   YVO₄:Eu;

the second fluorescent substance is composed of any one or more selectedfrom a fluorescent substance group consisting of:

-   -   RMg₂Al₁ ₆O₂ ₇:Eu, Mn (R is any one or both elements selected        from Sr and Ba);    -   RMgAl₁ ₀O₁ ₇:Eu, Mn (R is any one or both elements selected from        Sr and Ba);    -   ZnS:Cu;    -   SrAl₂O₄:Eu;    -   SrAl₂O₄:Eu, Dy;    -   ZnO:Zn;    -   Zn₂Ge₂O₄:Mn;    -   Zn₂SiO₄:Mn; and    -   Q₃MgSi₂O₈:Eu, Mn (Q is any one or more elements selected from        Sr, Ba and Ca); and

the third fluorescent substance is composed of any one or more selectedfrom a fluorescent substance group consisting of:

-   -   A₁ ₀(PO₄)₆Cl₂:Eu (A is any one or more elements selected from        Sr, Ca, Ba, Mg and Ce);    -   XMg₂Al₁ ₆O₂ ₇:E (X is any one or both elements selected from Sr        and Ba);    -   XMgAl₁ ₀O₁ ₇:Eu (X is any one or both elements selected from Sr        and Ba);    -   ZnS:Ag;    -   Sr₁ ₀(PO₄)₆Cl₂:Eu;    -   Ca₁ ₀(PO₄)₆F₂:Sb;    -   Z₃ MgSi₂O₈:Eu (Z is any one or more elements selected from Sr,        Ca and Ba);    -   SrMgSi₂O₈:Eu;    -   Sr₂P₂O₇:Eu;    -   CaAl₂O₄:Eu, Nd.

According to the above embodiment, when a semiconductor light-emittingelement having any emission wavelength in a range of 390 to 420 nm isused, monochromatic red, green or blue emission light can be obtained byselecting an appropriate fluorescent substance from a plurality offluorescent substances corresponding to emission wavelengths of thesemiconductor light-emitting element. Consequently, red, green and bluewavelength light beams are appropriately mixed and a white luminouscolor with a favorable color tone can be obtained. Furthermore,substantially light of all the wavelengths in the wavelength range ofthe semiconductor light-emitting element can be converted to red, greenor blue wavelengths by combining a plurality of fluorescent substances.Therefore, use efficiency of the outgoing light of the semiconductorlight-emitting element is improved and a semiconductor light-emittingdevice that emits white light in high efficiency can be obtained.

In one embodiment of the present invention, assuming the total amount as100 weight %,

the first fluorescent substance is between 50 weight % and 70 weight %inclusive;

the second fluorescent substance is between 7 weight % and 20 weight %inclusive; and

the third fluorescent substance is between 20 weight % and 30 weight %inclusive.

According to the above embodiment, since the first fluorescent substanceis between 50 weight % and 70 weight % inclusive, the second fluorescentsubstance is 7 weight % and 20 weight % inclusive and the thirdfluorescent substance is 20 weight % and 30 weight % inclusive,brightness of red light and blue light emitted from the firstfluorescent substance and the third fluorescent substance, respectively,which have low visibility, is enhanced as compared with green lightemitted from the second fluorescent substance. Therefore, inconsideration to human visibility, a semiconductor light-emitting devicethat emits white light with a favorable color tone can be obtained.

Here, when the mixture proportion of the first fluorescent substance isless than 50 weight %, the luminous color of the semiconductorlight-emitting device becomes white with a color tone tinged with green,whereas it becomes white with a color tone tinged with red when themixture proportion of the first fluorescent substance is more than 70weight %. Furthermore, when the mixture proportion of the secondfluorescent substance is less than 7 weight %, the luminous color of thesemiconductor light-emitting device becomes white with a color tonetinged with red, whereas it becomes white with a color tone tinged withgreen when the mixture proportion of the second fluorescent substance ismore than 20 weight %. Furthermore, when the mixture proportion of thethird fluorescent substance is less than 20 weight %, the luminous colorof the semiconductor light-emitting device becomes white with a colortone tinged with red, whereas it becomes white with a color tone tingedwith green when the mixture proportion of the third fluorescentsubstance is more than 30 weight %.

In one embodiment of the present invention, the sealing resin containsthe first, second and third fluorescent substances; and

the proportion of the total weight of the first, second and thirdfluorescent substances to the weight of the sealing resin is between 0.5and 1 inclusive.

According to the above embodiment, when the proportion of the totalweight of the first, second and third fluorescent substances to theweight of the sealing resin is between 0.5 and 1 inclusive, asemiconductor light-emitting device that emits white light close tonatural light can be obtained. When the proportion is more than 1,outgoing light from the semiconductor light-emitting device becomesbrighter and the color tone becomes pale. Meanwhile, when the proportionis less than 0.5, outgoing light from the semiconductor light-emittingdevice becomes darker and the color tone is tinged with red.

In one embodiment of the present invention, a light-emitting displaydevice comprises;

a light source using the semiconductor light-emitting device accordingto the present invention;

a light guiding plate for guiding light from the light source; and

red, green and blue color filters for transmitting light from the lightguiding plate and dividing the light; the light-emitting display device,wherein

outgoing light from the semiconductor light-emitting device has awavelength distribution that matches spectral characteristics of thecolor filters.

According to the embodiment, since the outgoing light from thesemiconductor light-emitting device has a wavelength distribution thatmatches spectral characteristics of the red, green and blue colorfilters, the color filters divide light into light having emissionwavelengths with its peak in a red color wavelength range, light havingemission wavelengths with its peak in a green color wavelength range andlight having emission wavelengths with its peak in a blue colorwavelength range while each having appropriate brightness. Therefore, asemiconductor light-emitting device that has light favorable useefficiency and high brightness can be obtained.

In one embodiment of the present invention, at least one of thefollowing is adjusted so that the wavelength distribution of theoutgoing light from the semiconductor light-emitting device matchesspectral characteristics of the color filters:

the emission wavelength of the semiconductor light-emitting element;

the emission wavelength of the first fluorescent substance;

the emission wavelength of the second fluorescent substance;

the emission wavelength of the third fluorescent substance;

the mixture proportions of the first, second and third fluorescentsubstances; and

the proportion of the total weight of the first, second and thirdfluorescent substances to the weight of the sealing resin.

According to the above embodiment, since the outgoing light from thesemiconductor light-emitting device is reliably and effectively adjustedso as to match spectral characteristics of the color filters, theoutgoing light from the light-emitting display device is divided intosubstantially red light, green light and blue light, which havemonochromatic colors and relatively high brightness, by the colorfilters. Therefore, the light-emitting display device has nodecoloration or the like and can achieve a full color display with highbrightness and contrast.

In one embodiment of the present invention, the light-emitting displaydevice is a liquid crystal display device.

According to the above embodiment, a liquid crystal display devicehaving almost no decoloration, but high brightness and contrast can beobtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIGS. 1A, 1B and 1C are cross sectional views showing a semiconductorlight-emitting element used in the present invention;

FIGS. 2A and 2B show an emission spectrum and an excitation spectrum,respectively, of a red luminous color from a fluorescent substance;

FIGS. 3A and 3B show an emission spectrum and an excitation spectrum,respectively, of a red luminous color from a fluorescent substancedifferent from the one in FIG. 2;

FIGS. 4A and 4B show an emission spectrum and an excitation spectrum,respectively, of a green luminous color from a fluorescent substance;

FIGS. 5A and 5B show an emission spectrum and an excitation spectrum,respectively, of a green luminous color from a fluorescent substancedifferent from the one in FIG. 4;

FIGS. 6A and 6B show an emission spectrum and an excitation spectrum,respectively, of a blue luminous color from a fluorescent substance;

FIGS. 7A and 7B show an emission spectrum and an excitation spectrum,respectively, of a blue luminous color from a fluorescent substancedifferent from the one in FIG. 6;

FIGS. 8A, 8B and 8C are cross sectional views showing a semiconductorlight-emitting device according to a first embodiment of the invention;

FIGS. 9A and 9B are cross sectional views showing a semiconductorlight-emitting device according to a second embodiment of the invention;

FIGS. 10A and 10B are cross sectional views showing a semiconductorlight-emitting device according to a third embodiment of the invention;

FIGS. 11A and 11B are cross sectional views showing a semiconductorlight-emitting device according to a fourth embodiment of the invention;

FIGS. 12A and 12B are cross sectional views showing a semiconductorlight-emitting device according to a fifth embodiment of the invention;

FIG. 13 is a cross sectional view showing a semiconductor light-emittingdevice according to a sixth embodiment of the invention;

FIGS. 14A and 14B are cross sectional views viewed from the front andside, respectively, showing a semiconductor light-emitting deviceaccording to a seventh embodiment of the invention;

FIGS. 15A and 15B are cross sectional views viewed from the front andside, respectively, showing a semiconductor light-emitting deviceaccording to an eighth embodiment of the invention;

FIGS. 16A and 16B are cross sectional views viewed from the front andside, respectively, showing a semiconductor light-emitting deviceaccording to a ninth embodiment of the invention;

FIGS. 17A and 17B are cross sectional views viewed from the front andside, respectively, showing a semiconductor light-emitting deviceaccording to a tenth embodiment of the invention;

FIGS. 18A, 18B and 18C show wavelength distributions of outgoing lightfrom the semiconductor light-emitting device in which contents of thefirst fluorescent substance, the second fluorescent substance and thethird fluorescent substance are different, respectively;

FIGS. 19A, 19B and 19C show wavelength distributions of outgoing lightfrom the semiconductor light-emitting device when the proportion of thetotal weight of the first, second and third fluorescent substances tothe weight of the sealing resin is 0.5, 0.66 and 1.0, respectively;

FIG. 20 shows an emission spectrum 150 of the semiconductorlight-emitting device shown in FIG. 19A and an effective emissionspectrum 152 of the semiconductor light-emitting device in considerationto human relative visibility 151;

FIG. 21 is a schematic view showing a light-emitting display deviceaccording to a twelfth embodiment of the invention; and

FIG. 22 shows spectral characteristics of color filters installed in thelight-emitting display device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described below in more detailwith reference to the accompanying drawings.

FIGS. 1A, 1B and 1C are cross sectional views showing a semiconductorlight-emitting element used in embodiments of the present invention.

FIG. 1A is a cross sectional view showing a semiconductor light-emittingelement having a substrate composed of an insulating semiconductormaterial. In this semiconductor light-emitting element 7 a, an N-typegallium nitride compound semiconductor layer 2, a P-type gallium nitridecompound semiconductor layer 3 and a P-type layer electrode 4 composedof a metallic thin film or a transparent conductive film aresuccessively laminated on an insulating sapphire substrate 1 a. AnN-type pad electrode 5 is formed on an exposed surface of the N-typegallium nitride compound semiconductor layer 2 formed on the right inFIG. 1A and a P-type pad electrode 6 is formed on the surface of theP-type layer electrode 4. When a current is allowed to flow between theN-type pad electrode 5 and the P-type pad electrode 6, light is emittedfrom a light-emitting region 8 a.

FIG. 1B is a cross sectional view showing a semiconductor light-emittingelement having a substrate composed of a conductive semiconductormaterial. In this semiconductor light-emitting element 7 b, an N-typegallium nitride compound semiconductor layer 2, a P-type gallium nitridecompound semiconductor layer 3 and a P-type layer electrode 4 composedof a metallic thin film or a transparent conductive film aresuccessively laminated on a conductive gallium nitride semiconductorsubstrate 1 b. An N-type pad electrode 5 is formed on the lower surfaceof the semiconductor substrate 1 b while a P-type pad electrode 6 isformed on the upper surface of the P-type layer electrode 4. When acurrent is allowed to flow between the N-type pad electrode 5 and theP-type pad electrode 6, light is emitted from a light-emitting region 8b.

FIG. 1C is a cross sectional view showing a semiconductor light-emittingelement of a type wherein light is allowed to pass through a substrateand taken out. In this semiconductor light-emitting element 7 c, anN-type gallium nitride compound semiconductor layer 2, a P-type galliumnitride compound semiconductor layer 3 and a P-type layer electrode 4composed of a metallic thin film or a transparent conductive film aresuccessively laminated on an insulating sapphire substrate 1 a (underthe sapphire substrate 1 a in FIG. 1C). An N-type pad electrode 5 isformed on an exposure surface of the N-type gallium nitride compoundsemiconductor layer 2 and a P-type pad electrode 6 is formed on asurface of the P-type layer electrode 4. As shown in FIG. 1C, the N-typepad electrode 5 and the P-type pad electrode 6 are directly ball-bondedto metallic wiring on a submount (not shown) or the like disposed belowthe semiconductor light-emitting element 7 c with, for example, metalbumps 16 a, 16 b composed of Au or the like. When a current is allowedto flow between the N-type pad electrode 5 and the P-type pad electrode6, light is emitted from a light-emitting region 8 c. This emissionlight is transmitted through the sapphire substrate 1 a and emittedupwards in FIG. 1C.

It is noted that the insulating sapphire substrate 1 a of thesemiconductor light-emitting elements 7 a, 7 c may be composed of othermaterials such as ZnO, GaN, SiC, ZnSe and so forth. The conductivegallium nitride semiconductor substrate 1 b in the semiconductorlight-emitting element 7 b may be composed of other materials such asSiC, ZnSe, Si and so forth. In the semiconductor light-emitting element7 b having this conductive semiconductor substrate 1 b, an electrode canalso be formed on the lower surface of the semiconductor substrate 1 bso that electrodes are formed on both the upper and lower surfaces ofthe semiconductor light-emitting element 7 b. Therefore, a largelight-emitting region can be formed on the semiconductor layer havingthe same size and this light-emitting element can be easily mounted ontoa lead frame or a mount substrate as compared with the semiconductorlight-emitting elements 7 a, 7 b, which have an insulator substrate 1 aand two electrodes disposed on one surface thereof.

As the material of the semiconductor layer in the semiconductorlight-emitting elements 7 a, 7 b, 7 c, nitride compound semiconductor(In_(x)Ga_(y)Al_(z)N (x+y+z=1, 0≦x≦1, 0≦y≦1, 0≦z≦1)) can be preferablyutilized, but, in addition to this, semiconductor materials such as SiC,ZnSe and so forth may be used.

The semiconductor light-emitting elements 7 a, 7 b, 7 c emit light in awavelength range of 390 nm to 420 nm, wherein human visibility of lightis very low. Therefore, when a fluorescent substance for convertinglight in this wavelength range into light in other wavelengths, onlycolors of the light converted by the fluorescent substance can berecognized as luminous colors. Thus, a semiconductor light-emittingdevice having favorable color tones can be obtained. When the wavelengthof light from the semiconductor light-emitting element is longer than420 nm, the light is easily recognized by human eyes as visible light.Therefore, the light whose wavelength is converted by the fluorescentsubstance is mixed with outgoing light directly from the semiconductorlight-emitting element and thus the color tone of the luminous color isdeteriorated. Furthermore, when the wavelength of light from thesemiconductor light-emitting element is shorter than 390 nm, this lightbecomes ultraviolet rays harmful to human bodies and has adverse effectson a resin portion used in the semiconductor light-emitting device. Forexample, lower brightness due to blackening of a mold resin or lowerreliability due to deterioration of the resin may occur.

Hereafter, the fluorescent substances used in the semiconductorlight-emitting device of the present invention are described in detail.

Tables 1 and 2 given below show the results of evaluation of brightnessof light emitted by exciting various fluorescent substances by using asemiconductor light-emitting element manufactured with a gallium nitridecompound semiconductor having an emission wavelength peak at 410 nm as alight-emitting element. These tables also show peak wavelengths (nm) oflight emitted by exciting the fluorescent substances. The brightness ofemission light was evaluated by comparing luminous brightness betweenrespective fluorescent substances in luminous colors of red, green,blue, blue green and orange. Symbol ⊚ was given to superior lightemission. Symbol ∘ was given to ordinary light emission. Symbol Δ wasgiven to slightly inferior light emission. Symbol x was given toinferior light emission. Table 1 shows peak wavelengths of fluorescentsubstances having luminous colors in red and green and the results ofevaluation in their brightness. Table 2 shows peak wavelengths offluorescent substances having luminous colors in blue, blue green andorange and the results of evaluation in their brightness.

TABLE 1 Emission peak Luminescent wavelength color Luminescent color(nm) Evaluation Red La₂O₂S: Eu 623 ⊚ Gd₂O₂S: Eu 625 ◯ Y₂O₂S: Eu 626 Δ0.5MgF₂•3.5MgO•GeO₂: Mn 658 ⊚ Y₂O₃: Eu 611 Δ Y(P,V)O₄: Eu 618 Δ YVO₄: Eu618 Δ CaS: Eu 655 ◯ CaS: Eu,Tm 650 ⊚ Green BaMg₂Al₁₆O₂₇: Eu,Mn 515 ◯BaMgAl₁₀O₁₇: Eu,Mn 512 ◯ ZnS: Cu 527 Δ SrAl₂O₄: Eu 522 ⊚ SrAl₂O₄: Eu,Dy522 ◯ ZnO: Zn 508 Δ Zn₂Ge₂O₄: Mn 537 ◯ Zn₂SiO₄: Mn 525 ◯ Ba₃MgSi₂O₈:Eu,Mn 512 ◯ Sr₃MgSi₂O₈: Eu,Mn 532 ◯

TABLE 2 Emission peak Luminescent wavelength color Fluorescent substance(nm) Evaluation Blue (Sr,Ca,Ba,Ce)₁₀(PO₄)₆Cl₂: Eu 457 ⊚ BaMg₂Al₁₆O₂₇: Eu455 ⊚ BaMgAl₁₀O₁₇: Eu 452 ◯ ZnS: Ag 450 Δ Sr₁₀(PO₄)₆Cl₂: Eu 447 ◯Ca₁₀(PO₄)₆F₂: Sb 480 Sr₃MgSi₂O₈: Eu 462 ◯ SrMgSi₂O₈: Eu 460 Δ SrAl₁₂O₁₉:Eu 400 X Sr₂P₂O₇: Eu 420 Δ CaAl₂O₄: Eu,Nd 440 Δ Blue green Sr₄Al₁₄O₂₅:Eu 492 ⊚ Sr₄Al₁₄O₂₅: Eu,Dy 492 ⊚ (Ba,Ca,Mg)₁₀(PO₄)₆Cl₂: Eu 482 ◯Sr₂Si₃O₈•2SrCl₂: Eu 490 Δ Orange ZnS: Mn 586 ◯ ZnS: Cu,Mn,Co 580 ◯

As shown in Table 1, to obtain a red luminous color with highbrightness, fluorescent substances such as La₂O₂S:Eu,0.5MgF₂.3.5MgO.GeO₂:Mn, CaS:Eu, Tm are preferred. To obtain a greenluminous color with high brightness, a fluorescent substance such asSrAl₂O₄:Eu is preferred. As shown in Table 2, to obtain a blue luminouscolor with high brightness, a fluorescent substance such as (Sr, Ca, Ba,Ce)₁ ₀(PO₄)₆Cl₂:Eu is preferred. To obtain a green luminous color withhigh brightness, fluorescent substances such as Sr₄Al₁ ₄O₂ ₅:Eu andSr₄Al₁ ₄O₂ ₅:Eu, Dy are preferred.

FIGS. 2 to 7 show emission spectra and excitation spectra of mainfluorescent substances used in the embodiments of the present invention.In all the graphs, the horizontal axis represents a wavelength (nm) andthe vertical axis represents relative intensity (%).

The emission wavelengths of the semiconductor light-emitting elementused in the present invention are in a wavelength range of from 390 to420 nm. More optimal emission wavelength ranges vary depending on thekind or luminous color of the fluorescent substance excited in responseto the emission wavelength of the semiconductor light-emitting element.

For example, when a red luminous color having an emission wavelengthpeak at 658 nm is obtained by the fluorescent substance0.5MgF₂.3.5MgO.GeO₂:Mn shown in FIG. 2A, it is effective that thefluorescent substance is excited by a semiconductor light-emittingelement having an emission wavelength peak in the wavelength range of410 to 420 nm as shown in FIG. 2B.

Meanwhile, when a red luminous color having an emission wavelength peakat 623 nm is obtained by the fluorescent substance La₂O₂S:Eu shown inFIG. 3A, it is effective that the fluorescent substance is excited by asemiconductor light-emitting element having an emission wavelength of390 nm as shown in FIG. 3B. Originally, the exciting wavelength peak ofthe fluorescent substance La₂O₂S:Eu are closer to the short wavelengthside than 390 nm. However, when the emission wavelength of thesemiconductor light-emitting element exciting the fluorescent substanceis shorter than 390 nm, ultraviolet rays harmful to human bodies areemitted, which is not practical. Furthermore, this light adverselyaffects the resin portion used in the semiconductor light-emittingdevice and causes lower brightness due to blackening of the sealingresin or lower reliability due to deterioration of the resin.

In addition to the above fluorescent substances, Gd₂O₂S:Eu, Y₂O₂S:Eu,Y₂O₃:Eu, Y(P, V)O₄:Eu, YVO₄:Eu and so forth can be used in theembodiments of the present invention. Furthermore, light can beconverted to red color light having an emission wavelength peak in arange of 600 to 670 nm by effectively using outgoing light from thesemiconductor light-emitting element while using a plurality of thesefluorescent substances.

Furthermore, when a green luminous color having an emission wavelengthpeak at 515 nm is obtained by the fluorescent substance BaMg₂Al₁ ₆O₂₇:Eu, Mn shown in FIG. 4A, it is effective that the fluorescentsubstance is excited by a semiconductor light-emitting element having anemission wavelength of 390 nm as shown in FIG. 4B.

Meanwhile, when a green luminous color having an emission wavelengthpeak at 522 nm is obtained by the fluorescent substance SrAl₂O₄:Eu shownin FIG. 5A, it is effective that the fluorescent substance is excited bya semiconductor light-emitting element having an emission wavelengthpeak in a wavelength range of 390 to 420 nm as shown in FIG. 5B.

Originally, the exciting wavelength peaks of the fluorescent substancesBaMg₂Al₁ ₆O₂ ₇:Eu, Mn and SrAl₂O₄:Eu are closer to the short wavelengthside than 390 nm. However, when the emission wavelength of thesemiconductor light-emitting element exciting the fluorescent substanceis shorter than 390 nm, ultraviolet rays harmful to a human body areemitted, which is not practical. Furthermore, this light adverselyaffects the resin portion used in the semiconductor light-emittingdevice and causes lower brightness due to blackening of the sealingresin or lower reliability due to deterioration of the resin.

In addition to the above fluorescent substances, ZnS:Cu, SrAl₂O₄:Eu, Dy,ZnO:Zn, Zn₂Ge₂O₄:Mn, Zn₂SiO₄:Mn, Ba₃MgSi₂O₈:Eu, Mn, Sr₃MgSi₂O₈:Eu, Mnand so forth can be used in the embodiments of the present invention.Furthermore, light can be converted to green color light having anemission wavelength peak in a range of 500 to 540 nm by effectivelyusing outgoing light from the semiconductor light-emitting element whileusing a plurality of these fluorescent substances.

Furthermore, when a blue luminous color having an emission wavelengthpeak at 457 nm is obtained by the fluorescent substance (Sr, Ca, Ba,Ce)₁ ₀(PO₄)₆Cl₂:Eu shown in FIG. 6A, it is effective that thefluorescent substance is excited by a semiconductor light-emittingelement having an emission wavelength peak in a wavelength range of 390to 400 nm as shown in FIG. 6B. Originally, the exciting wavelength peakof the fluorescent substance (Sr, Ca, Ba, Ce)₁ ₀(PO₄)₆Cl₂:Eu is closerto the short wavelength side than 390 nm. However, when the emissionwavelength of the semiconductor light-emitting element exciting thefluorescent substance is shorter than 390 nm, ultraviolet rays harmfulto a human body are emitted, which is not practical. Furthermore, thislight adversely affects the resin portion used in the semiconductorlight-emitting device and causes lower brightness due to blackening ofthe sealing resin or lower reliability due to deterioration of theresin.

Meanwhile, when a blue luminous color having an emission wavelength peakat 452 nm is obtained by the fluorescent substance BaMgAl₁ ₀O₁ ₇:Eushown in FIG. 7A, it is effective that the fluorescent substance isexcited by a semiconductor light-emitting element having an emissionwavelength of 390 nm as shown in FIG. 7B. Originally, the excitingwavelength peak of the fluorescent substance BaMgAl₁ ₀O₁ ₇:Eu is at 390nm. However, when the emission wavelength of the semiconductorlight-emitting element exciting the fluorescent substance is shorterthan 390 nm, ultraviolet rays harmful to a human body are emitted, whichis not practical. Furthermore, this light adversely affects the resinportion used in the semiconductor light-emitting device and causes lowerbrightness due to blackening of the sealing resin or lower reliabilitydue to deterioration of the resin.

In addition to the above fluorescent substance, BaMg₂Al₁ ₆O₂ ₇:Eu,ZnS:Ag, Sr₁ ₀(PO₄)₆Cl₂:Eu, Ca₁ ₀(PO₄)₆F₂:Sb, Sr₃MgSi₂O₈:Eu,SrMgSi₂O₈:Eu, Sr₂P₂O₇:Eu, CaAl₂O₄:Eu, Nd and so forth can be used in theembodiments of the present invention. Furthermore, outgoing light fromthe semiconductor light-emitting element can be effectively converted toblue color light having an emission wavelength peak in a range of 410 to480 nm by using a plurality of these fluorescent substances.

Furthermore, depending on the use purpose, outgoing light from thesemiconductor light-emitting element can be effectively converted toblue green light having an emission wavelength peak in a range of 480 to500 nm by using any one or more of fluorescent substances selected fromSr₄Al₁ ₄O₂ ₅:Eu, Sr₄Al₁ ₄O₂ ₅:Eu, Dy, (Ba, Ca, Mg)₁ ₀(PO₄)₆Cl₂:Eu,Sr₂Si₃O₈.2SrCl₂:Eu and so forth.

Furthermore, outgoing light from the semiconductor light-emittingelement can be converted to orange light having an emission wavelengthpeak in a range of 570 to 600 nm by using ZnS:Mn, ZnS:Cu or Mn, Co asthe fluorescent substances.

Hereafter, the semiconductor light-emitting devices according to theembodiments of the present invention are described in detail withreference to the accompanying drawings.

First Embodiment

FIGS. 8A to 8C are cross sectional views showing a semiconductorlight-emitting device according to a first embodiment of the invention.

FIG. 8A is a cross sectional view showing a lamp-type semiconductorlight-emitting device including a semiconductor light-emitting element 7a having an insulating substrate as shown in FIG. 1A, wherein thesemiconductor light-emitting element 7 a is sealed with a mold resin asa lamp-shaped sealing resin containing a dispersed fluorescentsubstance.

This semiconductor light-emitting device has a cup-shaped recessed mountsection 10 a at an end of a lead frame 101 as a base substance. Thesemiconductor light-emitting element 7 a is fixed on this cup-shapedmount section 10 a with an adhesive agent 11 composed of, for example,an epoxy resin or the like. A P-side electrode 6 a formed on the uppersurface of the semiconductor light-emitting element 7 a is connected toan electrode section 10 b of the lead frame 101 with a metallic wire 6 pcomposed of, for example, Au, Al, Cu or the like. Furthermore, an N-sideelectrode 5 a formed on the upper surface of the semiconductorlight-emitting element 7 a is connected to an electrode section 10 c ofa right-side lead frame 102 with a metallic wire 5 n. The semiconductorlight-emitting element 7 a and upper portions of the lead frames 101,102 are sealed with a mold resin 130 such as, for example, atransmissive epoxy resin or the like containing a dispersed fluorescentsubstance to form a lamp-shaped semiconductor light-emitting device. Theadhesive agent 11 for bonding the semiconductor light-emitting element 7a and the mount section 10 a of the lead frame 101 is not particularlylimited so long as its material does not absorb light from thesemiconductor light-emitting element 7 a. For example, a resin materialmixed with a metallic material having favorable heat conductivity toimprove a heat characteristic of the semiconductor light-emittingelement 7 a may be used. Also, a resin material containing a materialefficiently reflecting and scattering light from the semiconductorlight-emitting element 7 a towards the mount section 10 a of the leadframe 101 or the like may be used.

FIG. 8B is a cross sectional view showing a lamp-type semiconductorlight-emitting device including a semiconductor light-emitting element 7b having a conductive substrate as shown in FIG. 1B, wherein thesemiconductor light-emitting element 7 b is sealed with a mold resin 130as a lamp-shaped sealing resin containing a dispersed fluorescentsubstance.

In this figure, component members having the same functions as in thesemiconductor light-emitting device shown in FIG. 8A are designated bythe same reference numerals and their detailed explanations are omitted.

In this semiconductor light-emitting device, an N-side electrode section5 b of the semiconductor light-emitting element 7 b is directlyconnected to a mount section 10 a of a lead frame 101 with, for example,a conductive solder composed of a metal such as indium or the like or anadhesive agent 15 composed of an Au-epoxy resin, an Ag-epoxy resin orthe like. Meanwhile, a P-side electrode 6 b formed on the upper surfaceof the semiconductor light-emitting element 7 b is connected to anelectrode section 10 c of a right-side lead frame 102 in FIG. 8B with ametallic wire 6 p. The semiconductor light-emitting element 7 b andupper portions of the lead frames 101, 102 are sealed with a mold resin130 containing a dispersed fluorescent substance to form a lamp-shapedsemiconductor light-emitting device. Since the electrodes 6 b, Sb formedon the upper and lower surfaces of the semiconductor light-emittingelement 7 b are similar to a conventional GaAs or GaP semiconductorlight-emitting element, a lead frame used in a conventionalsemiconductor light-emitting device can be utilized as it is.

FIG. 8C is a cross sectional view showing a lamp-type semiconductorlight-emitting device including a semiconductor light-emitting element 7c having an insulating substrate as shown in FIG. 1C, wherein thesemiconductor light-emitting element 7 c and lead frames 103, 103 areconnected without using a metallic wire and the semiconductorlight-emitting element 7 c is sealed with a mold resin 130 as alamp-shaped sealing resin containing a dispersed fluorescent substances

In this semiconductor light-emitting device, a submount 17 as a basesubstance is connected to ends of lead frames 103, 103, which areopposed to each other. This submount 17 is composed of Si and hasinsulating property. Electrode interconnection wires 17 a, 17 b areformed on the upper surface of the submount 17. The semiconductorlight-emitting element 7 c is mounted on the upper surface of thesubmount 17 with a semiconductor layer surface (a lower surface of thesemiconductor light-emitting element 7 c in FIG. 1C) facing the submount17. A P-side electrode 6 c and an N-side electrode 5 c formed on thelower surface of the semiconductor light-emitting element 7 c areconnected to the electrode interconnection wires 17 a, 17 b formed onthe upper surface of the submount 17 by using Au bumps or the like. Theelectrode interconnection wires 17 a, 17 b formed on the upper surfaceof the submount 17 are connected to end portions 10 d, 10 e of the leadframes so as to be electrically connected to the outside. Furthermore,the semiconductor light-emitting element 7 c, the submount 17 and upperportions of the lead frames 103, 103 are sealed with a mold resin 130composed of an epoxy resin containing a dispersed fluorescent substanceto form a lamp-shaped semiconductor light-emitting device. Since thesemiconductor light-emitting element 7 c is directly connected to thesubmount 17 in this semiconductor light-emitting device, heat from alight-emitting region of the semiconductor light-emitting element 7 ccan be rapidly released to the outside of the semiconductorlight-emitting device via the submount 17 and the lead frames 103, 103.

The lamp-shaped semiconductor light-emitting devices shown in FIGS. 8A,8B and 8C emit light having a directivity upwards in FIGS. 8A, B and C.In particular, in the semiconductor light-emitting devices shown inFIGS. 8A and 8B, the mount section 10 a of the lead frame 101 is formedin a cup shape to efficiently collect light emitted from thesemiconductor light-emitting element 7 a, 7 b. In addition to an epoxyresin, transmissive thermosetting or thermoplastic resins such as asilicon resin, a urethane resin and a polycarbonate resin may be used asthe mold resin 130. Furthermore, the fluorescent substance may beuniformly dispersed in the whole mold resin 130, but when thefluorescent substance content rate is gradually increased from thesurface of the mold resin 130 towards the semiconductor light-emittingelement 7 a, 7 b, 7 c, deterioration of the fluorescent substance due toinfluences from the outside of the mold resin 130, such as moisture, canbe reduced. Furthermore, when the fluorescent substance content rate isgradually increased from the semiconductor light-emitting element 7 a, 7b, 7 c towards the surface of the mold resin 130, electrical and thermaleffects of semiconductor light-emitting element 7 a, 7 b, 7 c on thefluorescent substance can be relieved. Thus, the distribution of thefluorescent substance in the mold resin 130 can vary depending on thekind of the mold resin, the kind of the fluorescent substance, useenvironment, conditions, purposes and so forth.

Second Embodiment

FIGS. 9A and 9B are cross sectional views showing a semiconductorlight-emitting device according to a second embodiment of the invention.The semiconductor light-emitting device shown in FIG. 9A is the same asthe semiconductor light-emitting device shown in FIG. 8A except that afluorescent substance is filled in the mount section 10 a of the leadframe 101 and that the mold resin 131 does not contain the fluorescentsubstance. The semiconductor light-emitting device shown in FIG. 9B isalso the same as the semiconductor light-emitting device shown in FIG.8B except that a fluorescent substance is filled in the mount section 10a of the lead frame 101 and that the mold resin 131 does not contain thefluorescent substance. Therefore, component members having the samefunctions as in the semiconductor light-emitting devices shown in FIGS.8A and 8B are designated by the same reference numerals and theirdetailed explanations are omitted. This is applicable to the subsequentother embodiments.

In the semiconductor light-emitting device shown in FIGS. 9A and 9B, thesemiconductor light-emitting element 7 a, 7 b is disposed at the bottomof a cup-shaped mount section 10 a and a fluorescent substance 12 isfilled in this mount section 10 a so that the wavelength of light fromthe semiconductor light-emitting element 7 a, 7 b can be converted bythis fluorescent substance 12. That is, the fluorescent substance 12 isdisposed in the mount section 10 a for collecting light from thesemiconductor light-emitting element 7 a, 7 b so that all the light fromthe semiconductor light-emitting element 7 a, 7 b is converted withoutexception, thereby enhancing the light conversion efficiency. Therefore,color tones of the semiconductor light-emitting device are favorable ascompared with a case where the fluorescent substance is dispersed in thewhole mold resin as in the first embodiment. Furthermore, since thefluorescent substance needs to be disposed only in the mount section 10a, the amount of the used fluorescent substance can be reduced.

In the above embodiment, the fluorescent substance 12 was filled in thewhole mount section 10 a of the lead frame 101. However, so long aslight emitted from the semiconductor light-emitting element 7 a, 7 b canbe sufficiently converted to light having predetermined wavelengths, thefluorescent substance 12 does not necessarily need to be filled in thewhole mount section 10 a, but can be filled in a recessed shape in themount section 10 a. Alternatively, the fluorescent substance 12 may befilled so as to be swollen in a projected shape from the upper end ofthe mount section 10 a. That is, the fluorescent substance 12 only needsto be filled in the mount section 10 a in an amount in which thewavelength of light from the semiconductor light-emitting element 7 a, 7b can be converted to a desired wavelength.

Third Embodiment

FIGS. 10A and 10B are cross sectional views showing a semiconductorlight-emitting device according to a third embodiment of the invention.The semiconductor light-emitting device shown in FIG. 10A is the same asthe semiconductor light-emitting device shown in FIG. 9A except that aprecoating 13 a is disposed so as to cover the whole semiconductorlight-emitting element 7 a in the mount section 10 a of the lead frame101 and that the fluorescent substance 12 is disposed thereon. Thesemiconductor light-emitting device shown in FIG. 10B is the same as thesemiconductor light-emitting device shown in FIG. 9B except that aprecoating 13 a is disposed so as to cover the whole semiconductorlight-emitting element 7 a in the mount section 10 a of the lead frame101 and that the fluorescent substance 12 is disposed thereon.Therefore, component members having the same functions as in thesemiconductor light-emitting devices shown in FIGS. 9A and 9B aredesignated by the same reference numerals and their detailedexplanations are omitted.

In FIGS. 10A and 10B, a semiconductor light-emitting element 7 a, 7 b isdisposed at the bottom of a cup-shaped mount section 10 a formed at anend of a left-side lead frame 101. A precoating 13 a composed of, forexample, an epoxy resin, a silicon resin or a urethane resin is formedso as to cover the whole semiconductor light-emitting element 7 a, 7 b.A fluorescent substance 12 is disposed on this precoating 13 a in alayer so as to fill the inside of the mount section 10 a. Thefluorescent substance 12 is formed on the precoating 13 a by dipping themount section 10 a, in which the precoating 13 a is formed, or potting,spraying or vapor depositing the substance on the precoating 13 a in themount section 10 a. In FIGS. 10A and 10B, the fluorescent substance 12is formed only inside the mount section 10 a of the lead frame 101, butmay be formed so as to cover the whole upper surface of the lead frame101.

In the semiconductor light-emitting devices shown in FIGS. 10A and 10B,the fluorescent substance 12 is formed in a uniform thickness withsubstantially equal distances from the light-emitting region of thesemiconductor light-emitting element 7 a, 7 b by the precoating 13 a.Therefore, since the quantity of light that passes through thefluorescent substance 12 is substantially equal in all the regions, thissemiconductor light-emitting device can obtain uniform emission lightwithout unevenness. Furthermore, since the fluorescent substance 12 isdisposed at a position distant from the semiconductor light-emittingelement 7 a, 7 b, electrical and thermal effects of the semiconductorlight-emitting element on the fluorescent substance 12 can be relieved.As a result, a semiconductor light-emitting device having a favorablelight emitting characteristic and durability can be obtained.

Fourth Embodiment

FIGS. 11A and 11B are cross sectional views showing a semiconductorlight-emitting device according to a fourth embodiment of the invention.

In FIG. 11A, a semiconductor light-emitting element 7 a having aninsulating substrate is mounted on a printed circuit board 18 as a basesubstance and the semiconductor light-emitting element 7 a is sealedwith a mold resin 132 as a sealing resin containing a fluorescentsubstance dispersed.

In this semiconductor light-emitting device, a semiconductorlight-emitting element 7 a is bonded on a rectangular-solid-shapedprinted circuit board 18 composed of a glass epoxy, which has heatresistance, with an adhesive agent 11 composed of an epoxy resin. AP-side electrode 6 a and an N-side electrode 5 a formed on the uppersurface of this semiconductor light-emitting element 7 a are connectedto electrode sections 18 a, 18 b, respectively, on the upper surface ofthe printed circuit board 18 with metallic wires 6 p, 5 n. Theseelectrode sections 18 a, 18 b are led to the lower surface of theprinted circuit board 18 as a mounting surface via through holes (notshown) with a circular-arc cross section for connecting the uppersurface and the lower surface of the printed circuit board 18 and thenextend to both ends of this mounting surface. It is noted that aninsulating film may be used as the printed circuit board 18.

Subsequently, a mold resin 132 such as, for example, a transmissiveepoxy resin or the like as a sealing resin containing dispersedfluorescent substance is formed on the printed circuit board 18 so as tocover the whole semiconductor light-emitting element 7 a while having atrapezoidal cross section as shown in FIG. 11A. Thus, a semiconductorlight-emitting device in a chip component shape is formed.

The adhesive agent 11 for bonding the semiconductor light-emittingelement 7 a and the printed circuit board 18 is not limited so long asits material does not absorb light from the semiconductor light-emittingelement 7 a. For example, a resin material mixed with a metallicmaterial having favorable heat conductivity to improve a heatcharacteristic of the semiconductor light-emitting element 7 a, a resinmaterial containing a material for efficiently reflecting and scatteringlight from the semiconductor light-emitting element 7 a towards theprinted circuit board 18 or the like may used. However, when a resinmaterial containing a metallic material is used, an attention isrequired not to short-circuit the P-side electrode 6 a and the N-sideelectrode 5 a.

FIG. 11B is the same as the semiconductor light-emitting device shown inFIG. 11A except that the semiconductor light-emitting element 7 c havingan insulating substrate is included instead of the semiconductorlight-emitting element 7 a in FIG. 11A. Therefore, component membershaving the same functions as in the semiconductor light-emitting deviceshown in FIG. 11A are designated by the same reference numerals andtheir detailed explanations are omitted.

In the semiconductor light-emitting device in FIG. 11B, a semiconductorlight-emitting element 7 c emits light through an insulating substratedisposed on the upper side of the semiconductor light-emitting element 7c in FIG. 11B. In the semiconductor light-emitting element 7 c, a P-sideelectrode 6 c and an N-side electrode 5 c formed on a semiconductorlaminated side, which is the lower side in FIG. 11B, are directlyconnected to electrode sections 18 a and 18 b, respectively, on theprinted circuit board 18 via Au bumps. The semiconductor light-emittingelement 7 c may be mounted on a submount composed of Si or the like onwhich metallic wiring is provided in advance and the submount may beelectrically connected to the printed circuit board 18 by die bonding,wire bonding or the like. Since the semiconductor light-emitting element7 c is mounted with the semiconductor-laminated surface facing theprinted circuit board 18 in this semiconductor light-emitting device,heat can be rapidly released from a light-emitting region of thesemiconductor light-emitting element 7 c to the outside.

In addition to an epoxy resin, transmissive thermosetting orthermoplastic resins such as, for example, a silicon resin, a urethaneresin, a polycarbonate resin and so forth may be used as the mold resin132 of the semiconductor light-emitting devices in FIGS. 11A and 11B.Furthermore, the fluorescent substance may be uniformly disposed in thewhole mold resin 132, but, when the fluorescent substance content rateis gradually increased from the surface of the mold resin 132 towardsthe semiconductor light-emitting element, deterioration of thefluorescent substance due to influences such as moisture can be reduced.Furthermore, when the fluorescent substance content rate is graduallyincreased from the semiconductor light-emitting element 7 a, 7 c towardsthe surface of the mold resin 132, electrical and thermal effects of thesemiconductor light-emitting element 7 a, 7 c on the fluorescentsubstance can be relieved. Thus, the distribution of the fluorescentsubstance in the mold resin 132 can vary depending on the kind of themold resin, the kind of the fluorescent substance, use environment,conditions, purposes and so forth.

Instead of the semiconductor light-emitting element 7 a, 7 c, asemiconductor light-emitting element 7 b having a conductive substratemay be used. In this case, one electrode on the printed circuit board 18is directly connected to the N-type electrode formed on the lowersurface of the semiconductor light-emitting element 7 b with an adhesiveagent having conductivity. The P-side electrode formed on the uppersurface of the semiconductor light-emitting element 7 b is connected tothe other electrode section on the printed circuit board 18 with ametallic wire. Since the semiconductor light-emitting element 7 b haselectrodes on both the upper and lower surfaces of the semiconductorlight-emitting element 7 b as in the case of a conventional GaAs or GaPsemiconductor light-emitting device, a conventional lead frame can beutilized as it is.

Fifth Embodiment

FIGS. 12A and 12B are cross sectional views showing a semiconductorlight-emitting device according to a fifth embodiment of the invention.The semiconductor light-emitting device shown in FIG. 12A has a frame 19composed of a resin on a printed circuit board 18 as a base substance. Asemiconductor light-emitting element 7 b having a conductive substrateis disposed inside the resin frame 19 on the printed circuit board 18. Amold resin 134 as a sealing resin containing a fluorescent substance isfilled in the resin frame 19 to seal the semiconductor light-emittingelement 7 b.

In this semiconductor light-emitting device, a frame 19 composed of aresin is formed on a rectangular-solid-shaped printed circuit board 18composed of a glass epoxy, which has heat resistance. This resin frame19 has a height enough for the mold resin 134 filled therein to fullycover the semiconductor light-emitting element 7 b. In the frame 19, oneelectrode section 18 a on the printed circuit board 18 is connected toan N-side electrode 5 b on the lower surface of the semiconductorlight-emitting element 7 b by bonding with an adhesive agent havingconductivity. Meanwhile, a P-side electrode 6 b formed on the uppersurface of the semiconductor light-emitting element 7 b is connected tothe other electrode section 18 b on the printed circuit board 18 with ametallic wire 6 p. The electrode sections 18 a, 18 b are ledthree-dimensionally from the upper surface of the printed circuit board18 to the lower surface as a mounting surface and extend via throughholes (not shown) having a circular arc cross section that penetratethrough the printed circuit board 18 and then extend to both ends of thelower surface of the printed circuit board 18. The mold resin 134composed of a transmissive epoxy resin containing a dispersedfluorescent substance is filled in the resin frame 19 on the printedcircuit board 18 so as to cover the whole semiconductor light-emittingelement 7 b. Since the semiconductor light-emitting element 7 b haselectrodes 6 b, Sb on both the upper and lower surfaces of thesemiconductor light-emitting element 7 b as in the case of aconventional GaAs or GaP semiconductor light-emitting device, aconventional lead frame can be commonly utilized as it is. It is notedthat an insulating film may be used as the base substance in addition tothe printed circuit board 18.

The semiconductor light-emitting device in FIG. 12B has a resin frame 19a on a printed circuit board 18 as a base substance. A semiconductorlight-emitting element 7 c having an insulating substrate is disposedinside the resin frame 19 a, which is filled with a mold resin 134 assealing resin containing a dispersed fluorescent substance. Sidesurfaces of the resin frame 19 a facing the semiconductor light-emittingelement 7 c are inclined so that light emitted from the side surfaces ofthe semiconductor light-emitting element 7 c is reflected in thedirection perpendicular to the printed circuit board 18.

This semiconductor light-emitting device has a resin frame 19 a havinginclined side surfaces facing a semiconductor light-emitting element 7 con a rectangular-solid-shaped printed circuit board 18 composed of aglass epoxy. The semiconductor light-emitting element 7 c is mounted onthe printed circuit board 18 with the semiconductor-laminated surfacefacing downwards. A P-side electrode 6 c and an N-side electrode 5 c ofthe semiconductor light-emitting element 7 c are connected to electrodesections 18 a and 18 b, respectively, on the printed circuit board 18via Au bumps. As in the case of the semiconductor light-emitting deviceshown in FIG. 12A, the electrode sections 18 a, 18 b are ledthree-dimensionally from the upper surface of the printed circuit board18 to the lower surface as a mounting surface via through holes (notshown) and then extend to both ends of the lower surface of the printedcircuit board 18. It is noted that an insulating film may be used as thebase substance in addition to the printed circuit board 18. Thesemiconductor light-emitting element 7 c is directly connected to theprinted circuit board 18, but the semiconductor light-emitting element 7c may be mounted on a submount composed of Si, on which metallic wiringis provided in advance, and the submount may be electrically connectedto the printed circuit board 18 by die bonding, wire bonding or thelike.

Since the semiconductor-laminated surface of the semiconductorlight-emitting element 7 c is directly mounted on the printed circuitboard 18 in this semiconductor light-emitting device, heat from alight-emitting region of the semiconductor light-emitting element 7 ccan be rapidly released to the outside through the submount and the leadframes.

The mold resin 134 in the semiconductor light-emitting devices in FIGS.12A and 12B has the same material as that of the mold resins 13 in FIGS.8A, 8B and 8C. The distribution of the fluorescent substance in the moldresin can vary depending on the kind of the mold resin, the kind of thefluorescent substance, use environment, conditions, purposes and soforth.

In FIGS. 12A and 12B, the resin frame 19, 19 a is formed separately fromthe printed circuit board 18 and then bonded on the printed circuitboard 18. However, a part of a thick printed circuit board may beremoved to form a recessed portion so that the periphery of thisrecessed portion can be used as a frame. Furthermore, it may beconstituted such that a through hole is formed in the printed circuitboard 18, electrodes composed of a metal foil, which also serve asinterconnection wires, are disposed on the bottom surface of thisprinted circuit board 18, the semiconductor light-emitting element isdisposed on the electrodes/interconnection wires and the through holeportion is sealed with a sealing resin.

Furthermore, in the semiconductor light-emitting devices in FIGS. 12Aand 12B, the semiconductor light-emitting element 7 a shown in FIG. 1Amay be used instead of the semiconductor light-emitting element 7 b, 7c. When this semiconductor light-emitting element 7 a is used,electrodes of the semiconductor light-emitting element 7 a are connectedto the electrode sections of the printed circuit board 18 with metallicwires.

Sixth Embodiment

FIG. 13 is a cross sectional view showing a semiconductor light-emittingdevice according to a sixth embodiment of the invention.

This semiconductor light-emitting device has the same frame 19 a as theframe included in the semiconductor light-emitting device shown in FIG.12B. This frame 19 a is formed on the printed circuit board 18 composedof a glass epoxy as a rectangular-solid-shaped base substance. Sidesurfaces of the frame 19 a facing the semiconductor light-emittingelement 7 c are inclined so that light from side surfaces of thesemiconductor light-emitting element 7 c is reflected in the directionperpendicular to the printed circuit board 18. The semiconductorlight-emitting element 7 c is mounted on the printed circuit board 18with a semiconductor-laminated side facing downwards in FIG. 13 so thatlight is emitted from the upper substrate side in FIG. 13. Electrodes 6c, 5 c of this semiconductor light-emitting element 7 c are connected tothe electrode sections 18 a, 18 b of the printed circuit board 18 viabumps as in the case of the semiconductor light-emitting device shown inFIG. 12B. A mold resin 135 as a transmissive sealing resin composed ofan epoxy resin is filled in the frame 19 a disposed on the printedcircuit board 18 to seal the semiconductor light-emitting element 7 c. Afluorescent substance 12 is formed in a layer having a predeterminedlayer thickness on the frame 19 a and the mold resin 13.

Since the fluorescent substance 12 is formed in a uniform thickness at aposition in substantially equal distances from a light-emitting regionof the semiconductor light-emitting element 7 c in this semiconductorlight-emitting device of this embodiment, the quantity of light thatpasses through the fluorescent substance 12 is substantially consistentat any position of all the fluorescent substance 12 particles and thusuniform light without unevenness can be emitted. Furthermore, since thefluorescent substance 12 is formed with a predetermined distance fromthe semiconductor light-emitting element 7 c, electrical and thermaleffects of the semiconductor light-emitting element on the fluorescentsubstance 12 can be relieved.

In the above embodiment, the fluorescent substance 12 is also formed onthe upper surface of the resin frame 19 a. However, when the resin frame19 a is formed with a light-shielding material, the fluorescentsubstance 12 may be formed only on the mold resin 135. Furthermore,after the height of the resin frame 19 a is increased and the mold resin13 is filled to an extent that the upper end of the semiconductorlight-emitting element 7 c is slightly exceeded, the fluorescentsubstance may be disposed on the mold resin 135 in the resin frame 19 aby potting or the like.

As the resin frame 19 a, a part of a thick printed circuit board 18 maybe removed and the remaining protruded part may be used as a frame inthe same manner as described about the semiconductor light-emittingdevice in FIG. 12B. Furthermore, electrodes/interconnection wirescomposed of a metal foil may be formed at the bottom of a printedcircuit board 18 having a through hole to form a recessed portion.

Furthermore, although the efficiency of taking out light to the outsidedeclines, a resin frame that has vertically formed side surfaces facingthe semiconductor light-emitting element 7 c may be used.

It is noted that the semiconductor light-emitting element 7 a, 7 b shownin FIG. 1 may be used instead of the semiconductor light-emittingelement 7 c. In particular, since the semiconductor light-emittingelement 7 b having a conductive substrate has electrodes on both theupper and lower surfaces of the semiconductor light-emitting element 7b, which is the same electrode structure as that of a conventional GaAsor GaP semiconductor light-emitting device, a conventional lead framecan be utilized as it is.

Seventh Embodiment

FIGS. 14A and 14B are cross sectional views showing a semiconductorlight-emitting device according to a seventh embodiment of theinvention.

FIG. 14A is a cross sectional view of the semiconductor light-emittingdevice viewed from a light-emitting direction. FIG. 14B is a crosssectional view thereof viewed from a direction perpendicular to thelight-emitting direction.

In this semiconductor light-emitting device, a semiconductorlight-emitting element 7 a is bonded on a printed circuit board 18composed of glass epoxy as a rectangular-solid-shaped base substancewith an adhesive agent 11 composed of an epoxy resin or the like. AP-side electrode 6 c and an N-side electrode 5 c formed on the uppersurface of the semiconductor light-emitting element 7 a are connected toelectrode sections 18 a and 18 b, respectively, on the printed circuitboard 18 with metallic wires 6 p, 5 n. These electrode sections 18 a, 18b are led three-dimensionally to the lower surface via through holes 19,19 having a circular arc cross section that penetrates through theprinted circuit board 18 and then extend to both ends of a mountingsurface, which is the lower surface of the printed circuit board 18. Itis noted that an insulating film may be used instead of the printedcircuit board 18.

Furthermore, the whole semiconductor light-emitting element 7 a issealed with a mold resin 136 as a sealing resin composed of atransmissive epoxy resin containing a dispersed fluorescent substance.This mold resin 136 has a cross section substantially in a quarterellipse shape, wherein the left edge and the lower edge are straightlines, in FIG. 14B, while it has a rectangular cross section, whereinthe edge in the width direction is longer than the edge in the heightdirection, in FIG. 14A. Furthermore, a reflector 20 for reflecting lightfrom the semiconductor light-emitting element 7 a is formed on the moldresin 136.

As the mold resin 136, a thermosetting resin that has transmissivity andcan withstand a high temperature during solder reflow in the mountingprocess is preferably used. The mold resin is formed on the printedcircuit board 18 by a resin potting method, a transfer mold method, aninjection mold method or the like. The upper surface of the mold resin136 bends in a parabola as shown in FIG. 14B and the semiconductorlight-emitting element 7 a is disposed above the central line I-I ofthis parabola. Furthermore, a light-emitting surface A of the mold resin136 is planarly formed substantially on the same plane of the sidesurface of the printed circuit board 18. It is noted that the curvedsurface of the mold resin 136 may be formed so that the semiconductorlight-emitting element 7 a is positioned below the central line I-I ofthe parabola of the curved surface.

The reflector 20 contains at least a material for reflecting light fromthe semiconductor light-emitting element 7 a and light whose wavelengthis converted by the fluorescent substance 12. As in the case of the moldresin 136, the reflector is formed by using a thermosetting resin or athermoplastic resin that can withstand a high temperature during solderreflow by a resin potting method, a transfer mold method, an injectionmold method or the like so as to cover the upper surface of the moldresin 136. This reflector 20 bends while its lower edge end is broughtinto contact with the upper edge end of the mold resin 136 as shown inthe cross section in FIG. 14B, and formed such that the left edge end ison the same plane as the light-emitting surface A of the mold resin 136and that the right edge end of reflector 20 is a straight line leadingto the right end surface of the printed circuit board 18. Furthermore,the upper end edge of the reflector is formed in parallel to the printedcircuit board 18. In this semiconductor light-emitting device, theinterface between the upper surface of the mold resin 136 and the lowersurface of the reflector 20 is a reflecting surface. Light reflected bythis reflecting surface and emitted is diffused to the left side in thehorizontal direction in FIG. 14A, while blocked by the reflector 20 andthe printed circuit board 18 in the vertical direction. Therefore,direct light and light reflected from the light semiconductorlight-emitting element 7 a have a directing characteristic restricted tothe horizontal direction. The specific directing characteristic is thatthe half-value angle in illuminating light in the horizontal directionis ±65° and the half-value angle in the vertical direction is ±30°.Therefore, the wavelength of light from the semiconductor light-emittingelement 7 a is converted by the fluorescent substance 12 in the moldresin 136 and the light is directly emitted or reflected at thereflector 20 and emitted from the side surface of the mold resin 136 tothe outside. Thus, a side light-emitting type semiconductorlight-emitting device that has an effective illumination area wide inthe horizontal direction and high brightness can be provided.

It is noted that, since the reflector 20 needs to have a reflectingaction only in the portion brought into contact with the mold resin 136,a reflecting layer composed of, for example, a metal, a white paint orthe like may only need to be provided on the bent upper surface of themold resin 136 or the bent lower surface of the reflector 20.

The resin for bonding the semiconductor light-emitting element 7 a onthe printed circuit board 18 is not particularly limited so long aslight from the semiconductor light-emitting element 7 a is not absorbed.For example, a resin mixed with a metal having favorable heatconductivity to improve a heat characteristic of the semiconductorlight-emitting element 7 a, a resin material containing a material forefficiently reflecting and scattering light towards the mount section ofthe lead frame or the like may be used. However, when a resin containinga metal is used, an attention is required not to short-circuit a P-sideelectrode and an N-side electrode.

It is noted that the semiconductor light-emitting element 7 b shown inFIG. 1B having electrodes on both the upper and lower surfaces or thesemiconductor light-emitting element 7 c shown in FIG. 1C emitting lightfrom the substrate side may be used instead of the semiconductorlight-emitting element 7 a in the semiconductor light-emitting device ofthis embodiment. Since the semiconductor light-emitting element 7 b hasthe same electrode structure as that of a conventional GaAs or GaPsemiconductor light-emitting device, a conventional lead frame can beutilized as it is. Since the semiconductor-laminated surface of thesemiconductor light-emitting element 7 c is directly mounted on theelectric interconnection wires, heat from a light-emitting region can berapidly released to the outside through the submount and the leadframes.

Eighth Embodiment

FIGS. 15A and 15B are cross sectional views showing a sidelight-emitting type semiconductor light-emitting device according to aneighth embodiment of the invention.

FIG. 15A is a cross sectional view of this semiconductor light-emittingdevice viewed from a light-emitting direction. FIG. 15B is a crosssectional view thereof viewed from a direction perpendicular to thelight-emitting direction. The semiconductor light-emitting device inFIGS. 15A and 15B is the same as the semiconductor light-emitting devicein FIGS. 14A and 14B except that a semiconductor light-emitting element7 b having electrodes on the upper and lower surfaces is used and that afluorescent substance 12 is provided in a layer on a light-emittingsurface A side of a mold resin 137 as a sealing resin without dispersingthe fluorescent substance in the sealing resin. Therefore, componentmembers having the same functions are designated by the same referencenumerals and their detailed explanations are omitted.

In this side light-emitting type semiconductor light-emitting device,the fluorescent substance 12 is formed in a uniform layer thickness withsubstantially equal distances from a light-emitting region of thesemiconductor light-emitting element 7 b. Therefore, since the quantityof light that passes through the fluorescent substance 12 is constantlyconsistent substantially in all the regions, uniform emission lightwithout unevenness can be emitted. Furthermore, since the fluorescentsubstance 12 is disposed at a position distant from the semiconductorlight-emitting element 7 b, electrical and thermal effects of thesemiconductor light-emitting element 7 b on the fluorescent substance 12can be relieved. Furthermore, since the type that has electrodes on boththe upper and lower surfaces of the semiconductor light-emitting element7 b has the same electrode structure as that of a conventional GaAs orGaP semiconductor light-emitting device, a conventional lead frame canbe utilized as it is.

In the above embodiment of the present invention, the semiconductorlight-emitting element 7 a in FIG. 1A or the semiconductorlight-emitting element 7 c in FIG. 1C may be used instead of thesemiconductor light-emitting element 7 b.

Ninth Embodiment

FIGS. 16A and 16B are cross sectional views showing a sidelight-emitting type semiconductor light-emitting device according to aninth embodiment of the invention.

FIG. 16A is a cross sectional view of this semiconductor light-emittingdevice viewed from a light-emitting direction. FIG. 16B is a crosssectional view thereof viewed from a direction perpendicular to thelight-emitting direction. In this semiconductor light-emitting device, amold resin 139 as sealing resin for sealing a semiconductorlight-emitting element 7 c is formed on a printed circuit board 18 as abase substance. This mold resin 139 has a cross section substantially ina half ellipse shape in FIG. 16A, looking as if a lower half of anellipse is removed, and a cross section substantially in a quarterellipse shape in FIG. 16B, looking as if the left-side and lowerportions of an ellipse are removed. That is, the surface of the moldresin 139 excluding a light-emitting surface A constitutes a dome shapehaving a predetermined radius of curvature on the printed circuit board18. Furthermore, a fluorescent substance layer 12 a as a fluorescentsubstance is formed so as to cover a curved surface portion of theoutside surface of this mold resin 139. A reflector 20 for reflectinglight from the semiconductor light-emitting element 7 c is furtherformed on its outside surface.

Furthermore, a barrier body 21 as a shielding body for shielding lightso as not to emit light from the semiconductor light-emitting element 7c directly to the outside is formed on the light-emitting surface A sideof the semiconductor light-emitting element 7 c on the printed circuitboard 18. This barrier body 21 has a height and width enough to shieldthe light-emitting region of the semiconductor light-emitting element 7c viewed from the light-emitting surface A side of the semiconductorlight-emitting device (see FIG. 16A) and is formed by using a resin, ametal or the like that does not transmit light from the semiconductorlight-emitting element 7 c. Furthermore, a material that absorbs lightcan be utilized as a material of the barrier body 21. In this case,however, light use efficiency is deteriorated. Furthermore, a barrierbody 21 a composed of a resin frame surrounding the semiconductorlight-emitting element 7 c may be used as shown with a broken line inFIG. 16B. Furthermore, to shield light directly emitted from thesemiconductor light-emitting element 7 c, a recessed portion may beformed in a part of a thick printed circuit board and the semiconductorlight-emitting element may be disposed in this recessed portion so thatthe light-emitting region is hidden. Since the semiconductorlight-emitting element 7 c is mounted on the printed circuit board 18 bydirectly connecting the semiconductor-laminated side, heat from thelight-emitting region can be rapidly released through the submount andthe lead frames. Furthermore, since the light-emitting region of thesemiconductor light-emitting element is positioned in the lower portion,the height of the barrier body can be reduced, thereby achieving highlight use efficiency. It is noted that the shielding bodies 21, 21 a andthe recessed portion can be used in the semiconductor light-emittingdevice of the seventh embodiment shown in FIGS. 14A and 14B.

After the wavelength of outgoing light from the semiconductorlight-emitting element 7 c is converted by the fluorescent substancelayer 12 a, the outgoing light is reflected by the reflector 20 broughtinto contact with this fluorescent substance layer 12 a and thewavelength is converted by the fluorescent substance layer 12 a again.Then, the light is emitted to the outside of the semiconductorlight-emitting device. Therefore, this semiconductor light-emittingdevice has wavelength conversion efficiency substantially twice as highas that of a semiconductor light-emitting device having a fluorescentsubstance disposed in the light-emitting direction so as to transmitlight from the semiconductor light-emitting element. Therefore, since asufficient wavelength conversion effect can be expected even when thefluorescent substance layer 12 a is made thinner, the amount of the usedfluorescent substances can be reduced, thereby reducing costs formanufacturing the semiconductor light-emitting device.

The fluorescent substance layer 12 a in the above embodiment convertsthe wavelength by transmitting light. A fluorescent substance that doesnot transmit light, but converts the wavelength and reflects the lightcan be formed as a reflector. Such examples include a fluorescentsubstance wherein its fine particles reflect and scatter light and thesurfaces are coated with a fluorescent material or the like.

In this embodiment, the semiconductor light-emitting elements 7 a, 7 bin FIGS. 1A and 1B may be used instead of the semiconductorlight-emitting element 7 c. In particular, since the semiconductorlight-emitting element 7 b having a conductive substrate has the sameelectrode structure similar to that of a conventional GaAs or GaPsemiconductor light-emitting device that has electrodes on both theupper and lower surfaces, a conventional lead frame can be utilized asit is.

Tenth Embodiment

FIGS. 17A and 17B are cross sectional views showing a sidelight-emitting type semiconductor light-emitting device according to atenth embodiment of the invention.

FIG. 17A is a cross sectional view of this semiconductor light-emittingdevice viewed from a light-emitting direction. FIG. 17B is a crosssectional view thereof viewed from a direction perpendicular to thelight-emitting direction. This embodiment is the same as the ninthembodiment shown in FIGS. 16A and 16B except that the semiconductorlight-emitting element 7 b having a conductive substrate is used insteadof the semiconductor light-emitting element 7 c and that a printedcircuit board 18 a as a base substance constituted by attaching anultrathin printed circuit board 23 composed of a metal foil providedwith electrodes/interconnection wires at the bottom surface composed ofa glass epoxy substrate having a through hole B is used instead of theprinted circuit board 18.

As shown in FIGS. 17A and 17B, in this side light-emitting typesemiconductor light-emitting device, the semiconductor light-emittingelement 7 b is formed on the ultrathin printed circuit board 23 so as tobe hidden in the through hole B in the printed circuit board 18 a.Therefore, since the thickness of the printed circuit board 18 a ishigher than the semiconductor light-emitting element 7 b, thesemiconductor light-emitting device can be made thinner. Since alight-emitting region of the semiconductor light-emitting element 7 b iscompletely hidden from the outside, light from the semiconductorlight-emitting element 7 b is not directly emitted to the outside. Thatis, since only light whose wavelength is converted by a fluorescentsubstance layer 12 a as a fluorescent substance is emitted outside ofthe semiconductor light-emitting device, color tones of thesemiconductor light-emitting device are further improved. It is notedthat the through hole B needs to be deep only enough to hide at leastthe light-emitting region of the semiconductor light-emitting element 7b when viewed from the light-emitting surface A (see FIG. 17B) side.

In the above embodiment, the semiconductor light-emitting element 7 a, 7c shown in FIGS. 1A and 1C may be used instead of the semiconductorlight-emitting element 7 b. In particular, since the light-emittingregion is positioned near the bottom of the through hole B when thesemiconductor light-emitting element 7 c is disposed in the through holeB, the semiconductor light-emitting device can be further made thinner.

Eleventh Embodiment

FIGS. 18A, 18B and 18C and FIGS. 19A, 19B and 19C show wavelengthdistributions of light emitted from a semiconductor light-emittingdevice according to an eleventh embodiment of the invention. Thissemiconductor light-emitting device has a semiconductor light-emittingelement on a base substance. Outgoing light of this semiconductorlight-emitting element has a light-emitting wavelength peak at 410 nm ina wavelength range of 390 to 420 nm. Furthermore, this semiconductorlight-emitting device has first, second and third fluorescentsubstances, which converts the outgoing light of the semiconductorlight-emitting element. The semiconductor light-emitting element issealed with a sealing resin composed of a resin that is not damaged bythis semiconductor light-emitting element. The first, second and thirdfluorescent substances are contained in this sealing resin while mixedin a substantially uniform manner. The first fluorescent substance iscomposed of 0.5MgF₂.3.5MgO.GeO₂:Mn fluorescent substance and excited byoutgoing light of the semiconductor light-emitting element to emit redlight having emission wavelengths with its main peak at 658 nm. Thesecond fluorescent substance is composed of SrAl₂O₄:Eu fluorescentsubstance and emits green light having emission wavelengths with itsmain peak at 522 nm. The third fluorescent substance is composed ofBaMgAl₁ ₀O₁ ₇:Eu fluorescent substance and emits blue light havingemission wavelengths with its main peak at 452 nm. This semiconductorlight-emitting device emits white light by mixing colors of the outgoinglight from the first, second and third fluorescent substances and isused as a light source for a backlight for a display device of acellular phone, a mobile data terminal, a personal computer or the like.It is noted that the emission wavelength peak of the semiconductorlight-emitting element is in the wavelength range of 390 to 420 nm, butmore preferably in the wavelength range of 400 to 420 nm.

FIGS. 18A, 18B and 18C show changes in the wavelength distributions ofthe outgoing light when the mixture proportions of the first, second andthird fluorescent substances are changed in this semiconductorlight-emitting device. In all the graphs, the horizontal axis representswavelength (nm) and the vertical axis represents relative intensity (%).Furthermore, the proportion of the total weight of the first, second andthird fluorescent substances to the weight of the sealing resin is 0.5in each case.

FIG. 18A shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device containing 47 weight % of the firstfluorescent substance, 13 weight % of the second fluorescent substanceand 40 weight % of the third fluorescent substance, assuming that thetotal amount of the first, second and third fluorescent substances is100 weight %. The outgoing light of the semiconductor light-emittingdevice becomes white with a color tone tinged with green in this case.

FIG. 18B shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device containing 56 weight % of the firstfluorescent substance, 11 weight % of the second fluorescent substanceand 33 weight % of the third fluorescent substance, assuming that thetotal amount of the first, second and third fluorescent substances is100 weight %. The outgoing light of the semiconductor light-emittingdevice becomes white with a favorable color tone in this case.

FIG. 18C shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device containing 65 weight % of the firstfluorescent substance, 26 weight % of the second fluorescent substanceand 9 weight % of the third fluorescent substance, assuming that thetotal amount of the first, second and third fluorescent substances is100 weight %. The outgoing light of this semiconductor light-emittingdevice become white with a color tone tinged with red, so-called neutralwhite, in this case.

A semiconductor light-emitting device containing La₂O₂S:Eu as the firstfluorescent substance, BaMg₂ Al₁ ₆O₂ ₇:Eu, Mn as the second fluorescentsubstance and (Sr, Ca, Mg, Ce)₁ ₀(PO₄)₆Cl₂:Eu as the third fluorescentsubstance in proportion of 72 weight %, 7 weight % and 21 weight %,respectively, was formed. The outgoing light of this semiconductorlight-emitting device was favorable white light. Furthermore, asemiconductor light-emitting device containing the first, second andthird fluorescent substances in proportion of 58 weight %, 22 weight %and 20 weight %, respectively, also obtained favorable white outgoinglight. In consideration to the above experimental results, it was foundthat the luminous color of the semiconductor light-emitting devicebecame white with a color tone tinged with green when the mixtureproportion of the first fluorescent substance, that is, red lightemitting fluorescent substance was less than 50 weight %, while whitewith a color tone tinged with red was obtained when the mixtureproportion of the first fluorescent substance was more than 70 weight %.Furthermore, it was found that the luminous color of the semiconductorlight-emitting device became white with a color tone tinged with redwhen the mixture proportion of the second fluorescent substance, thatis, green light emitting fluorescent substance was less than 7 weight %,while white with a color tone tinged with green was obtained when themixture proportion of the second fluorescent substance was more than 20weight %. Furthermore, it was found that the luminous color of thesemiconductor light-emitting device became white with a color tonetinged with red when the mixture proportion of the third fluorescentsubstance, that is, blue light emitting fluorescent substance was lessthan 20 weight %, while white with a color tone tinged with green wasobtained when the mixture proportion of the third fluorescent substanceis larger than 30 weight %. Therefore, the semiconductor light-emittingdevice of the eleventh embodiment can obtain favorable white outgoinglight when the proportion of the total weight of the first to thirdfluorescent substances to the weight of sealing resin is 0.5 and themixture proportions of the first, second and third fluorescentsubstances are 56 weight %, 11 weight % and 33 weight %, respectively.

FIGS. 19A, 19B and 19C show changes in the wavelength distributions ofthe outgoing light when the proportion of the total weight of the first,second and third fluorescent substances to the weight of the sealingresin is changed in this semiconductor light-emitting device. In all thegraphs, the horizontal axis represents wavelength (nm) and the verticalaxis represents relative intensity (%). Furthermore, in each case, themixture proportions of the first, second and third fluorescentsubstances are 65 weight %, 26 weight % and 9 weight %, respectively,assuming that the total amount of the first, second and thirdfluorescent substances is 100 weight %.

FIG. 19A shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device when the proportion of the totalweight of the first, second and third fluorescent substances to theweight of the sealing resin is 0.5. The outgoing light of thissemiconductor light-emitting device becomes white with a color tonetinged with red, so-called neutral white, in this case.

FIG. 19B shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device when the proportion of the totalweight of the first, second and third fluorescent substances to theweight of the sealing resin is 0.66. The outgoing light of thesemiconductor light-emitting device becomes white with a favorable colortone in this case.

FIG. 19C shows a wavelength distribution of the outgoing light from thesemiconductor light-emitting device when the proportion of the totalweight of the first, second and third fluorescent substances to theweight of the sealing resin is 1.0. The outgoing light of thesemiconductor light-emitting device becomes white with a color tonetinged with green in this case.

From FIGS. 19A, 19B and 19C, the semiconductor light-emitting device canobtain white outgoing light with a favorable color tone when the mixtureproportions of the first, second and third fluorescent substances are 65weight %, 26 weight % and 9 weight %, respectively, and the proportionof the total weight of the first to third fluorescent substances to theweight of sealing resin is between 0.5 and 1.0 inclusive.

FIG. 20 shows an effective emission spectrum 152 of the semiconductorlight-emitting device in consideration to the emission spectrum 150 ofthe semiconductor light-emitting device shown in FIG. 19A and humanrelative visibility 151. The horizontal axis represents wavelength (nm)and the vertical axis represents relative intensity (%).

As shown in FIG. 20, the emission spectrum 150 of the semiconductorlight-emitting device has a wider emission wavelength range than thewavelength range of human relative visibility 151. Since the effectiveemission spectrum 152 of the wavelength range that covers the wavelengthrange of the relative visibility 151 can be obtained, a white luminouscolor having a favorable color tone for the human visual sense can beachieved.

Furthermore, since the sealing resin is a resin that is not damaged byoutgoing light from the semiconductor light-emitting element in thesemiconductor light-emitting device, this sealing resin does not suffertrouble such as, for example, blackening or the like. Therefore, troublesuch as lower brightness of the semiconductor light-emitting device orthe like can be prevented and thus the semiconductor light-emittingdevice can maintain stable performances over a long period.

In the above semiconductor light-emitting device, by using a pluralityof kinds of fluorescent substances as the first, second and thirdfluorescent substances, the wavelength range of the effective emissionspectrum 152 may be made substantially equal to the wavelength range ofthe human relative visibility 151. Consequently, luminous colors of thesemiconductor light-emitting device can have favorable color tones.Furthermore, since the emission wavelength range of the semiconductorlight-emitting device needs to cover only the human visible range, thelight-emitting efficiency of the semiconductor light-emitting device canbe improved.

In the semiconductor light-emitting device of this embodiment, thefirst, second and third fluorescent substances are mixed substantiallyuniformly into the sealing resin for sealing the semiconductorlight-emitting element. However, after only the first, second and thirdfluorescent substances are mixed, this fluorescent substance mixture maybe disposed in a layer on the sealing resin surface or the first, secondand third fluorescent substances may be provided separately inrespective layers on the sealing resin surface. In this case, it ispreferable in consideration to the light emitting and absorbingwavelengths or the like that these layers are disposed in the order ofthe emission wavelength of each fluorescent substance contained in thelayer from the side closer to the semiconductor light-emitting elementtowards the side farther therefrom, the one with the shortest wavelengthfirst. Furthermore, the semiconductor device of this embodiment may beformed in the same structure as that of the semiconductor light-emittingdevices of the above-described first to tenth embodiments. Consequently,white light can be emitted with a favorable color tone in lamp-type,chip component type and side light-emitting type semiconductorlight-emitting devices.

Twelfth Embodiment

FIG. 21 is a schematic view showing a light-emitting display deviceaccording to a twelfth embodiment of the invention. This light-emittingdisplay device 200 is a liquid crystal display device having a lightsource 201 composed of the semiconductor light-emitting device of theeleventh embodiment, a light guiding plate 202 for guiding light 205from the light source 201 and a liquid crystal panel 203 including colorfilters for dividing light from this light guiding plate 202.

The light source 201 may be formed by using any one of the semiconductorlight-emitting devices of the first to eleventh embodiments. Inparticular, when the light-emitting display device 200 is used as adisplay device of a cellular phone, a mobile data terminal, a personalcomputer or the like, the semiconductor light-emitting device that emitswhite light as in the same manner as in the eleventh embodiment ispreferred as the light source 201. Furthermore, when the first, secondand third fluorescent substances used in the semiconductorlight-emitting device of the eleventh embodiment are used as thefluorescent substance for the semiconductor light-emitting devices ofthe fourth to sixth embodiments, a chip-component-shaped semiconductorlight-emitting device that can emit white light can be obtained. Sincethis semiconductor light-emitting device has a chip component shape, itcan be readily handled when mounted on the light-emitting display device200. Furthermore, since this chip-component-shaped semiconductorlight-emitting device can be directly attached to a side surface 202 aof the light guiding plate 202, emission light can be efficiently guidedto the light guiding plate 202. Furthermore, when a light source 201 ais constituted by using a semiconductor light-emitting device obtainedby mounting the fluorescent substances of the eleventh embodiment on thesemiconductor light-emitting devices of the seventh to tenthembodiments, the thickness of the light-emitting display device 200 inthe light-emitting direction of the light guiding plate 202 can beeffectively reduced by attaching the semiconductor light-emitting deviceon a side surface 202 a of the light guiding plate 202 so that theprinted circuit board 18 as a base substance is substantially inparallel to the light guiding plate 202 since this semiconductorlight-emitting device is of a side light-emitting type. A plurality ofsemiconductor light-emitting devices are used for this light source 201,but the light source may also be constituted by one semiconductorlight-emitting device so long as the light intensity is sufficient.

The light guiding plate 202 is formed by using, for example, apolycarbonate resin, an acrylic resin or the like. When alight-reflecting section is formed on a side surface 202 a, into whichlight from the light source 201 is introduced, and surfaces other thanthe light-emitting surface 202 b, from which the introduced light isemitted, light from the light source 201 can be efficiently emitted fromthe light-emitting surface 202 b. Furthermore, light to the lightguiding plate 202 may be introduced not only from one side surface 202a, but may be introduced from, for example, two side surfaces opposed toeach other, or three or four side surfaces. Furthermore, to make theintensity of light emitted from the light-emitting surface 202 buniform, a light-scattering agent may be mixed in the light guidingplate 202 or the bottom surface in FIG. 21, which is opposed to thelight-emitting surface 202 b, may be inclined so that light introducedfrom the side surface 202 a of the light guiding plate 202 is reflectedat the inclined bottom surface and emitted from the light-emittingsurface 202 b. When a light-scattering pattern is provided on the bottomsurface, the intensity of light 206 from the light-emitting surface 202b can be made further uniform.

The liquid crystal panel 203 has two transparent substrates each havinga transparent electrode, a liquid crystal sealed between the twosubstrates, a polarizing plate and color filters bonded on thesubstrates. As the color filters, red, green and blue color filters areformed corresponding to a plurality of picture elements, wherein thequantity of light that is transmitted through the liquid crystal isadjusted by signals applied to the transparent electrodes. The red,green and blue color filters are formed by coloring a sheet formed bypolycarbonate, polyethylene terephthalate or the like in red, green andblue by using a light-transmitting dye, a pigment or the like so thatpicture elements in a fine honeycomb shape or a delta array shape areformed.

FIG. 22 shows spectral characteristics of the color filters. Referencenumeral 210 represents a spectral characteristic of a red color filter.Reference numeral 211 represents a spectral characteristic of a greencolor filter. Reference numeral 212 represents a spectral characteristicof a blue color filter. The wavelength distribution of light from thelight source 201 is adjusted so as to match the spectral characteristics210, 211, 212 of these color filters. More specifically, in asemiconductor light-emitting device constituting a light source 201, theemission wavelength of the semiconductor light-emitting element, theemission wavelength and mixture proportions of the first, second andthird fluorescent substances, mixture proportion of the total weight ofthe first to third fluorescent substances to the weight of the sealingresin and so forth are adjusted so that the wavelength distribution ofthe light 205 from the light source 201 matches the spectralcharacteristics 210, 211, 212 of the color filters. For example, thesemiconductor light-emitting device having the wavelength distributionin FIG. 19B having favorable color tones matches the spectralcharacteristics in FIG. 22. This is because the mixture proportion ofthe total weight of the first to third fluorescent substances to theweight of the sealing resin is adjusted to match the above spectralcharacteristics in this semiconductor light-emitting device. Thus, thelight source 201 has a wavelength distribution that matches spectralcharacteristics of the color filters. Therefore, when the light 205 fromthis light source 201 is guided to the liquid crystal panel 203 via thelight guiding plate 202, the light is divided into substantiallyhomogeneous red, green and blue light 207 with high brightness by thecolor filters of this liquid crystal panel 203. As a result, thislight-emitting display device 200 can display an image or picture havingfavorable color tones as well as high brightness and contrast.

The invention being thus described, it will be obvious that theinvention may be varied in many ways. Such variations are not beregarded as a departure from the spirit and scope of the invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. A light-emitting display device comprising: a light source comprisinga semiconductor light-emitting device constituted by mounting asemiconductor light-emitting element on a base substance and sealing thesemiconductor light-emitting element and fluorescent substances by asealing resin; a light guiding plate for guiding light from the lightsource; and red, green and blue color filters for transmitting lightfrom the light guiding plate and dividing the light; the light-emittingdisplay device, wherein the semiconductor light-emitting element emitslight having an emission wavelength only in a range of 390 to 420 nm,the light having visibility lower than light in a visible range morethan 420 nm; only a first fluorescent substance, a second fluorescentsubstance and a third fluorescent substance are included in thefluorescent substances; the first fluorescent substance has red outgoinglight having emission wavelengths with its main emission peak in awavelength range of 600 to 670 nm; the second fluorescent substance hasgreen outgoing light having emission wavelengths with its main emissionpeak in a wavelength range of 500 to 540 nm; the third fluorescentsubstance has blue outgoing light having emission wavelengths with itsmain emission peak in a wavelength range of 410 to 480 nm; the sum ofcolors of light emitted from the first, second and third fluorescentsubstances is a white color; outgoing light from the semiconductorlight-emitting device has a wavelength distribution that matchesspectral characteristics of the color filters; the following is adjustedso that the wavelength distribution of the outgoing light from thesemiconductor light-emitting device matches spectral characteristics ofthe color filters: the emission wavelength of the semiconductorlight-emitting element; the emission wavelength of the first fluorescentsubstance; the emission wavelength of the second fluorescent substance;the emission wavelength of the third fluorescent substance; the mixtureproportions of the first, second and third fluorescent substances; andthe proportion of the total weight of the first, second and thirdfluorescent substances to the weight of the sealing resin.